HomeMy WebLinkAbout20180328.tiffWELD COUNTY
CODE ORDINANCE 2017-10
IN THE MATTER OF REPEALING AND REENACTING, WITH AMENDMENTS, CHAPTER 30
WELD COUNTY DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT ON -SITE
WASTEWATER TREATMENT SYSTEM REGULATIONS, OF THE WELD COUNTY CODE
BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF THE COUNTY OF
WELD, STATE OF COLORADO:
WHEREAS, the Board of County Commissioners of the County of Weld, State of
Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with
the authority of administering the affairs of Weld County, Colorado, and
WHEREAS, the Board of County Commissioners, on December 28, 2000, adopted Weld
County Code Ordinance 2000-1, enacting a comprehensive Code for the County of Weld,
including the codification of all previously adopted ordinances of a general and permanent nature
enacted on or before said date of adoption, and
WHEREAS, the Weld County Code is in need of revision and clarification with regard to
procedures, terms, and requirements therein.
NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
County of Weld, State of Colorado, that certain existing Chapters of the Weld County Code be,
and hereby are, repealed and re-enacted, with amendments, and the various Chapters are
revised to read as follows.
CHAPTER 30
WELD COUNTY DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT
ON -SITE WASTEWATER TREATMENT SYSTEM REGULATIONS
TABLE OF CONTENTS
ARTICLE I Authority
Sec. 30-1-10. Title.
Sec. 30-1-20. Jurisdiction, severability, savings clause.
Sec. 30-1-30. Effective date.
ARTICLE II Scope and Purpose
Sec. 30-2-10. Declaration.
Sec. 30-2-20. Purpose.
Sec. 30-2-30. Effluent discharged to surface waters.
ARTICLE III Definitions
Sec. 30-3-10. Definitions.
Sec. 30-3-20. Abbreviations and acronyms.
Table 30-3-1 Abbreviations and Acronyms
ARTICLE IV Administration and Enforcement
Sec. 30-4-10. General sanitation requirements.
Sec. 30-4-20. Existing OWTS review.
Sec. 30-4-30. Permit application requirements and procedures.
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Sec. 30-4-40.
Sec. 30-4-50.
Sec. 30-4-60.
Sec. 30-4-70.
Sec. 30-4-80.
Sec. 30-4-90.
Sec. 30-4-100.
Sec. 30-4-110.
Sec. 30-4-120.
Sec. 30-4-130.
Sec. 30-4-140.
Sec. 30-4-150.
Sec. 30-4-160.
Sec. 30-4-170.
Determination of compliance of permit submission.
Denial of permit application.
Access to site.
Notification and inspection stages.
Final approval of OWTS permit.
Systems employing new technology.
Product Development Permit.
Systems contractor license.
Regulations of systems cleaners.
Variance procedure.
General prohibitions.
Prohibition of on -site wastewater treatment systems in unsuitable areas.
Enforcement.
Penalties.
ARTICLE V Site and Soil Evaluation
Sec. 30-5-10.
Sec. 30-5-20.
Sec. 30-5-30.
Sec. 30-5-40.
Sec. 30-5-50.
Sec. 30-5-60.
Sec. 30-5-70.
Sec. 30-5-80.
Sec. 30-5-90.
Site and soil evaluation general requirements.
Preliminary investigation.
Reconnaissance.
Detailed soil investigation.
Marking of Soil Profile Pit Excavations or Percolation holes.
Report and site plan.
Design document.
Site Protection.
Qualifications for a Competent Technician.
Delete Sec. 30-5-100.
ARTICLE VI Wastewater Flow and Strength
Sec. 30-6-10. Wastewater flows.
Table 30-6-1 Single -Family Residential Design Flows
Table 30-6-2 Estimate of Average Daily Wastewater Flow and BOD5 Load Per
Person Unless Otherwise Noted
Sec. 30-6-20. Wastewater strength.
Table 30-6-3 Treatment Levels
Table 30-6-4 High Strength Wastewater
ARTICLE VII Minimum Distances Between Components of an On -Site Wastewater Treatment
System and Physical Features
Sec. 30-7-10. Minimum horizontal distances.
Sec. 30-7-20. Dry gulches, cut banks and fill areas.
Sec. 30-7-30. On -site Wastewater Treatment System design consideration and treatment
requirements - separation distances from soil treatment area.
Table 30-7-1 Minimum Horizontal Distances in Feet Between Components of
and On -Site Wastewater Treatment System Installed after November 15,
1973 and Water, Physical and Health Impact Features
Table 30-7-2 On -site Wastewater Treatment System Design Consideration
and Treatment Requirements — Separation Distances from Soil Treatment
Area
ARTICLE VIII Design Criteria - General
Sec. 30-8-10. Performance.
Sec. 30-8-20. Reliability.
Sec. 30-8-30. Accessibility for inspection, maintenance and servicing.
Sec. 30-8-40. Plumbing codes.
Sec. 30-8-50. Electrical equipment.
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Sec. 30-8-60. Indicators of failure or malfunctioning for systems utilizing mechanical
apparatus.
Sec. 30-8-70. Sampling access.
Sec. 30-8-80. Component operating instructions.
Sec. 30-8-90. Surface activity.
Sec. 30-8-100. Floodplains.
Sec. 30-8-110. Business, commercial, industrial, institutional or multi -family dwelling
wastewater systems.
ARTICLE IX Design Criteria - Components
Sec. 30-9-10. Tanks and vaults.
Sec. 30-9-20. Septic tanks.
Table 30-9-1 Minimum Septic Tank Size Based on Number of Bedrooms
Sec. 30-9-30. Abandonment of tank.
Sec. 30-9-40. Pipe standards and bedding requirements.
Sec. 30-9-50. Cleanouts.
Sec. 30-9-60. Distribution Box.
Sec. 30-9-70. Drop Box.
Sec. 30-9-80. Stepdown/Relief Pipe.
Sec. 30-9-90. Wastewater Pumping and Dosing Siphon Systems.
Sec. 30-9-100. Effluent Screens.
Sec. 30-9-110. Grease Interceptor Tanks
ARTICLE X Design Criteria - Soil Treatment Area
Sec. 30-10-10. General.
Sec. 30-10-20. Calculation of infiltrative surface of soil treatment area.
Table 30-10-1 Soil Treatment Area Long-term Acceptance Rates by Soil
Texture, Soil Structure, Percolation Rate and Treatment Level
Table 30-10-1A Design Criteria for Soils with High Rock Content (Type
"R" Soils) 1, 2, 3, 4
Sec. 30-10-30. Allowable soil treatment area reductions and increases.
Table 30-10-2 Size Adjustment Factors for Methods of Application in Soil
Treatment Areas
Table 30-10-3 Size Adjustment Factors for Types of Distribution Media in
Soil Treatment Areas
Sec. 30-10-40. Design of distribution systems.
Sec. 30-10-50. Soil Treatment Area Requirements.
Sec. 30-10-60. Storage/Distribution Media.
Sec. 30-10-70. Lift stations.
Sec. 30-10-80. Soil replacement.
Sec. 30-10-90. Repairs.
ARTICLE XI Design Criteria - Higher Level Treatment Systems
Sec. 30-11-10. General.
Sec. 30-11-20. Treatment levels.
Sec. 30-11-30. Sand filters.
Sec. 30-11-40. Mound Systems.
Sec. 30-11-50. Rock plant filter (constructed wetland) treatment before soil treatment area
ARTICLE XII Design Criteria - Other Facilities
Delete Sec. 30-12-10.
Sec. 30-12-10. Evapotranspiration and evapotranspiration/absorption systems.
Table 30-12-1 Graduation of Wicking Sand for Evapotranspiration Beds.
Delete Sec. 30-12-30.
Sec. 30-12-20. Vaults other than vault privies.
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Sec. 30-12-30. Vault Privies.
Sec. 30-12-40. Incinerating, composting and chemical toilets.
Sec. 30-12-50. Treatment systems other than those discharging through soil treatment area
or sand filter system.
ARTICLE XIII Operation and Maintenance
Sec. 30-13-10. Responsibility.
Sec. 30-13-20. Service label.
Sec. 30-13-30. Monitoring and sampling.
ARTICLE XIV TECHNOLOGY REVIEW AND ACCEPTANCE
Sec. 30-14-10. Technology Review and Acceptance
ARTICLE XV MATERIALS INCORPORATED BY REFERENCE
Sec. 30-15-10. Material Incorporated by Reference
APPENDIX
APPENDIX 30-A - TEXTURAL TRIANGLE DEFINING TWELVE TEXTURAL CLASSES OF
THE USDA (ILLUSTRATED FOR A SAMPLE CONTAINING 37% SAND, 45% SILT AND 18%
CLAY)
APPENDIX 30-B - SOIL CLASSIFICATION SYSTEM (SOIL -SEPARATE SIZE LIMITS)
APPENDIX 30-C - ANNUAL FREE WATER SURFACE EVAPORATION MAP OF WELD
COUNTY ADAPTED FROM NOAA TR NWS 33 UNITS: INCHES/YEAR ARTICLE I - Authority
ARTICLE I - AUTHORITY
Amend Sec. 30-1-20. Jurisdiction, Severability, Savings Clause.
A. These Regulations are promulgated by the Weld County Board of County Commissioners
under the authority of the Weld County Home Rule Charter, Section 3-8, acting as the Weld
County Board of Public Health under authority of the Weld County Home Rule Charter, and
upon the recommendation of the advisory Board of Public Health established pursuant to
said Charter. The jurisdiction of these Regulations extends to all territories within Weld
County including all incorporated and unincorporated areas.
B. thru E. — No change.
F. Chapter coverage. These Regulations adopted by the Weld County Board of Public Health,
pursuant to current On -site Wastewater Treatment System Regulations of the Colorado
Department of Public Health and Environment, Water Quality Control Commission,
Regulation #43 (5 CCR 1002-43) and adopted in compliance with Section 25-10-104, C.R.S.,
shall govern all aspects of permits, performance, location, construction, alteration, installation
and use of On -site Wastewater Treatment Systems of less than or equal to two thousand
(2,000) gallons per day design capacity. Site approval, design review and a discharge permit
from the Water Quality Control Division are required for a system with design capacity greater
than two thousand (2,000) gallons per day average flow.
Amend Sec. 30-1-30. Effective date.
Upon adoption, the Regulations shall become effective upon the twelfth day of February,
2018. Until the twelfth day of February, 2018, Chapter 30 Code provisions in effect prior to the
changes contained in these Regulations shall remain in effect.
ARTICLE II - Scope and Purpose
Amend Sec. 30-2-10. Declaration.
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A. — No change.
B. This regulation will apply to On -site Wastewater Treatment Systems as defined in Article Ill
of this Chapter.
Amend Sec. 30-2-30. Effluent discharged to surface waters.
Any system that will discharge into surface waters must be designed by a professional
engineer. The discharge permit application must be submitted for preliminary approval to the
Board of Public Health. Once approved by the Board of Public Health, the application must be
submitted to the Water Quality Control Division for review in accordance with the Water Quality
Control Act, Section 25-8-101, et seq., C.R.S., and all applicable regulations of the Water Quality
Control Commission. Compliance with such a permit will be deemed full compliance with this
Regulation.
ARTICLE III - Definitions
Amend Sec. 30-3-10. Definitions.
The following definitions shall apply in the interpretation and enforcement of these
Regulations. The words "shall", and "must" as used herein, indicates a mandatory requirement.
Accessible means easily reached, attained or entered by the necessary equipment or
maintenance provider.
Basal Area means the effective surface area available to transmit the treated effluent from the
filter media in a mound system into the in -situ receiving soils. The perimeter is measured at the
interface of the imported fill material and in -situ soil. On sloping sites, only the area down -gradient
from the up -slope edge of the distribution media may be included in this calculation.
Bed means a below -grade soil treatment area with a level sub -base, consisting of a shallow
excavation greater than three (3) feet wide containing distribution media and more than one (1)
lateral.
Bedroom means, a room with an egress window, a closet, and/or is intended for sleeping
purposes; or as defined by the local board of health, as stated in the local OWTS regulation.
Cistern means an underground, enclosed unpressurized reservoir or tank for storing water
as part of a potable water supply system.
Colorado Plumbing Code means Rules and Regulations of the Colorado State Plumbing
Board (3 CCR 720-1).
Competent technician means a person who has the appropriate expertise and is able to
conduct and interpret the results of soil profile test pit excavations, percolation tests, and site
evaluations. This individual has also met the required competencies for a "Competent
Technician" as defined in Section 30-5-90.
Composting toilet means a self-contained waterless toilet designed to decompose non -water -
carried human wastes through microbial action and to store the resulting matter for disposal.
Consistence means the degree and kind of cohesion and adhesion that soil exhibits and/or
the resistance of soil to deformation or rupture under an applied stress to an extent that the soil
density would restrict soil permeability. Aspects of consistence are used to determine if the
horizon will have permeability lower than that of the defined soil type. Additional insight to
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consistence can be found in the USDA - NRCS Field book for Describing and Sampling Soils;
Version 3.0, Sept. 2012.
Cut -bank means a nearly vertical slope caused by erosion or construction that has exposed
historic soil strata.
Deep gravel system means a soil treatment area for repairs only where the trenches utilize a
depth of gravel greater than six (6) inches below the distribution pipe and sidewall area is allowed
according to a formula specified in this Regulation.
Deficiency. See Malfunction.
Distribution box means a watertight component that receives effluent from a septic tank or
other treatment unit and distributes effluent via gravity in approximately equal portions to two (2)
or more distribution laterals in the soil treatment area.
Domestic wastewater treatment works means a system or facility for treating, neutralizing,
stabilizing or disposing of domestic wastewater, which system or facility has a designed capacity
to receive more than two thousand (2,000) gallons of domestic wastewater per day. The term
domestic wastewater treatment works also includes appurtenances to such system or facility,
such as outfall sewers and pumping stations, and to equipment related to such appurtenances.
Domestic wastewater treatment works does not include industrial wastewater treatment plants or
complexes whose primary function is the treatment of industrial wastes, notwithstanding the fact
that human wastes generated incidentally to the industrial process are treated therein. Section
25-8-103(5), C.R.S.
Dosing, pressure means a uniform application of wastewater throughout the intended portion
of the soil treatment area through small diameter pipes and orifices, under pressure. For this
definition, the term pressure indicates that the system is capable of creating upward movement
of effluent out of the distribution system piping.
Effective size means the size of granular media such that ten percent (10%) by weight of the
media is finer than the size specified.
Effluent pipe means nonperforated pipe that conveys effluent from one (1) On -site
Wastewater Treatment System component to the next.
Delete Experimental system.
Failure means a condition existing within any component of an OWTS which prevents the
system from functioning as intended, and which results in the discharge of untreated or partially
treated wastewater onto the ground surface, into surface water or ground water, or which results
in the back-up of sewage into the building sewer. Other conditions within an OWTS component
that are deemed by a local public health agency to be a threat to public health and/or safety
may also be deemed a failure.
Floodplain, 100 -year means an area adjacent to a stream which is subject to flooding as the
result of the occurrence of a one -hundred -year flood, and is so adverse to past, current or
foreseeable construction or land use as to constitute a significant hazard to public or
environmental health and safety or to property, or is designated by the Federal Emergency
Management Agency (FEMA) or National Flood Insurance Program (NFIP). In the absence of
FEMA/NFIP maps, a professional engineer must certify the floodplain elevations.
Floodway means the channel of a river or other watercourse and the adjacent land areas that
must be reserved in order to discharge the base flood without cumulatively increasing the water
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surface elevation more than one-half (1/2) foot (six [6] inches) at any point or as designated by
the Federal Emergency Management Agency or National Flood Insurance Program. In the
absence of FEMA/NFIP maps, a professional engineer must certify the floodway elevation and
location.
Flow, design means the estimated volume of wastewater per unit of time for which a
component or system is designed. Design flow may be given in the estimated volume per unit,
such as person per unit time, that must be multiplied by the maximum number of units that a
facility can accommodate over that time.
Higher level treatment means designated treatment levels other than treatment level 1. (See
Table 30-6-3).
Holding tank. See vault.
Infiltrative surface means designated interface where effluent moves from distribution media
or a distribution product into treatment media or original soil. In standard trench or bed systems
this will be the interface of the distribution media or product and in -situ soil. Two separate
infiltrative surfaces will exist in a mound system and an unlined sand filter; one at the interface of
the distribution media and fill sand, the other at the interface of the fill sand and in -situ soil.
Lateral means a pipe, chamber or other conveyance used to carry and to distribute effluent.
Delete Limiting condition.
Limiting layer means a horizon or condition in the soil profile or underlying strata that limits
the treatment capability of the soil or severely restricts the movement of fluids. This may include
soils with low or high permeability, impervious or fractured bedrock, or a seasonal or current
ground water surface.
Linear Loading Rate means the amount of effluent applied per linear foot along the contour
(gpd/linear ft.).
Liner means an impermeable synthetic or natural material used to prevent or restrict
infiltration and/or exfiltration. For the purposes of this regulation, the minimum thickness of a liner
must be 30 ml.
Long -Term Acceptance Rate (LTAR) means a design parameter expressing the rate that
effluent enters the infiltrative surface of the soil treatment area at equilibrium, measured in volume
per area per time, e.g. gallons per square foot per day (gal/ft 2/day).
Malfunction means the condition in which a component is not performing as designed or
installed and is in need of repair in order to function as originally intended.
Manufactured media. See Media, other manufactured.
Media, Enhanced Manufactured means an accepted proprietary manufactured distribution
product, other than a chamber, wrapped in a specified fabric, and placed on a specified sand
base or media that does not mask the infiltrative surface of the in -situ soil.
Media, other manufactured means an accepted proprietary manufactured distribution product
made of synthetic media for distribution of effluent that is placed directly on the in -situ soil.
Mound means a soil treatment area whereby the infiltrative surface is at or above original
grade at any point.
Pressure distribution. See Dosing, pressure.
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Record Drawing means construction drawings provided to illustrate the progress or
completion of the installation of an OWTS, or components of the OWTS; typically based on field
inspections by the designer or local public health agency.
Remediation system means a treatment system, chemical/biological additive or physical
process that is proposed to restore the soil treatment area of an OWTS to intended performance.
Repair means restoration of functionality and/or treatment by reconstruction, relocation, or
replacement of an on -site sewage wastewater treatment system or any component thereof in
order to allow the system to function as intended.
Delete Restrictive layer.
Replacement System. See Repair.
Sand filter means an engineered designed OWTS that utilizes a layer of specified sand as
filter and treatment media and incorporates pressure distribution.
Sand filter, lined means an engineered designed OWTS that has an impervious liner and
under -drain below the specified sand media. Lined sand filters may be intermittent/single pass,
where the effluent is distributed over the sand bed a single time before distribution to a soil
treatment area, or recirculating, where part of the effluent is returned to an earlier component for
additional treatment before distribution to a soil treatment area.
Sand filter, unlined means an engineered designed OWTS that includes a layer of specified
sand used as a treatment media without a liner between the sand and the existing soil on which
it is placed.
Sequential distribution means a distribution method in which effluent is loaded into one (1)
trench and fills it to a predetermined level before passing through a relief pipe or device to the
succeeding trench. The effluent does not pass through the distribution media before it enters
succeeding trenches.
Serial distribution means a distribution method in which effluent is loaded into one (1) trench
and fills it to a predetermined level before passing through a relief pipe or device to the succeeding
trench. The effluent passes through the distribution media before entering succeeding trenches
which may be connected to provide a single uninterrupted flow path.
Delete Soil profile hole.
Soil profile test pit excavation means a trench or other excavation used for access to evaluate
the soil horizons for properties influencing effluent movement, bedrock, evidence of seasonal high
groundwater and other information to be used in locating and designing an On -site Wastewater
Treatment System.
Soil treatment area means the physical location where final treatment and dispersal of
effluent occurs. Soil treatment area includes drainfields, mounds and drip fields.
Suitable soil means a soil which will effectively treat and filter effluent by removal of
organisms and suspended solids which meets long-term acceptance rate requirements as defined
in Table 30-10-1, and has the required vertical thickness below the infiltrative surface and above
a limiting layer.
Volume, effective means the amount of effluent contained in a tank under normal operating
conditions; for a septic tank, effective volume is determined relative to the invert of the outlet.
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For a dosing tank, the effective volume under normal conditions is determined relative to the invert
of the inlet and the control off level.
Wastewater, high strength means:
1. Wastewater from a structure having BOD 5 greater than three hundred (300) mg/L;
and/or TSS greater than two hundred (200) mg/L; and/or fats, oils and grease greater
than fifty (50) mg/L; or
2. Effluent from a septic tank or other pretreatment component (as defined by NSF/ANSI
Standard 40 testing protocol) that has BOD greater than one hundred eighty (180) mg/L;
and/or TSS greater than eighty (80) mg/L; and/or fats, oils and grease greater than
twenty-five (25) mg/L and is applied to an infiltrative surface.
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Amend Sec. 30-3-20. Abbreviations and acronyms.
Amend Table 30-3-1 Abbreviations and Acronyms
Abbreviation/Acronym Full Title
AASHTO
ANSI
ASTM
BOD
C.R.S.
CBOD
CSA
gpd
IAPMO
ISDS
LTAR
mg/L
MPI
NAWT
NDDS
NPCA
NSF
OWTS
American Association of State Highway and Transportation Officials
American National Standards Institute
American Society for Testing and Materials
Biochemical Oxygen Demand
Colorado Revised Statutes
Carbonaceous Biochemical Oxygen Demand
Canadian Standards Association
gallons per day
International Association of Plumbing and Mechanical Officials
Individual Sewage Disposal System
Long-term Acceptance Rate
milligrams per liter
Minutes per Inch
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National Association of Wastewater Technicians
Non -pressurized Drip Dispersal System
National Precast Concrete Association
National Sanitation Foundation
On -site Wastewater Treatment System
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STA
TL
TN
TSS
UL
Soil Treatment Area
Treatment Level
Total Nitrogen
Total Suspended Solids
Underwriters' Laboratories
ARTICLE IV - Administration and Enforcement
Amend Sec. 30-4-30. Permit application requirements and procedures.
A. thru C.13. — No changes.
14. Other information, data, plans, specifications and tests as required by the Division,
including but not limited to:
a. Additional evaluation: When the Division representative has determined that the
Division does not have sufficient information for evaluation of an application or a
system, the Division representative may require additional tests or documentation.
b. Additional hydrological, geological or engineering: When specific evidence suggests
undesirable soil conditions exist, additional hydrological, geological, engineering or
other information provided by a professional engineer or geologist may be required
to be submitted by the applicant. This requirement will not prejudice the right of the
Division to develop its own information from its own sources.
c. Any expenses associated with additional information, data, plans, specifications and
tests shall be the responsibility of the party obtaining the permit.
D. and E. — No change.
F. Other fees.
1. Reinspection fee. The Division may assess a reinspection fee as established by the
Board of County Commissioners for each inspection or reinspection when such portion
of work for which inspection is called is not complete or when corrections called for are
not ready.
2. Surcharge. The Division must collect a fee of twenty-three dollars ($23.00) for each
permit issued for a new, repaired or upgraded OWTS. Of that fee, the Division must
retain three dollars ($3.00) to cover the Division's administrative costs and twenty dollars
($20.00) must be transmitted to the State Treasurer, who must deposit that sum in the
Water Quality Control Fund created in Section 25-8-502(1)(c), C.R.S.
G. and H. — No change.
I. A permit must be required for the expanded use of an OWTS. The OWTS must be replaced
or modified to handle the increased design flow unless it is determined that the existing
system is adequately designed and constructed for the higher design flow rate.
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J. The issuance of a permit and specification of terms and conditions therein will not constitute
assumption of liability nor create a presumption that the County or its officers, employees or
agents may be liable for the failure or malfunctioning of any system. Permit issuance will not
constitute a certification that the system, the equipment used in the system, or any
component used for system operation will ensure continuous compliance with the provision
of the OWTS Act, applicable sections of these Regulations adopted thereunder or any terms
and conditions of a permit.
Remainder of Section — No change.
Amend Sec. 30-4-40. Determination of compliance of permit submission.
A. and B. — No change.
C. No permits shall be issued for the following systems unless they are designed by a
professional engineer and until they have been reviewed and approved by the Board of Public
Health:
1. Product Development Permits.
2. Treatment systems other than those discharging through a soil treatment area or a sand
filter system.
Amend Sec. 30-4-80. Final approval of OWTS permit.
A. Final approval of the OWTS permit by the Division must include, but is not limited to:
1. Receipt of letter from the professional engineer certifying construction of the OWTS as per
the approved design, if the OWTS was engineer -designed;
2. Receipt of a record drawing which includes a scale drawing showing all components of
the OWTS, including their location from known and findable points, dimensions, depths,
sizes, manufacturers' names and models as available, and other information relative to
locating and maintaining the OWTS components;
3. Final inspection prior to backfilling the OWTS by the Division, confirming that it was
installed according to the permit requirements and regulations or variances to the
regulations; and
4. Identification of the systems contractor.
Amend Sec. 30-4-90. Systems employing new technology.
Systems employing new technology may be considered by the Division, provided they have
been reviewed and accepted by the Water Quality Control Division according to Section 43.13 of
On -site Wastewater Treatment System Regulation #43, as adopted in 2017. The Division
prohibits the reduction of system size, or the reduction in vertical or horizontal separation when
higher level treatment systems are used.
Delete Sec. 30-4-100. - Experimental systems in its entirety and replace with the following:
Sec. 30-4-100. Product Development Permit
A. For products that have not received Colorado Water Quality Control Division acceptance, the
manufacturer may apply to the local public health agency for a product development permit.
Requirements for proprietary treatment component acceptance are in Regulation 43-5 CCR
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1002-43. The Division prohibits the reduction of system, size, or the reduction in vertical or
horizontal separation when higher level treatment systems are used.
B. For products or types of systems which have not been otherwise accepted by the Colorado
Water Quality Control Division pursuant to section 43.13.D of Regulation 43, the Board of
Public Health may approve an application for product development permit only if the system
has been designed by a professional engineer, and only if the application provides proof of
the ability to install a replacement OWTS in compliance with all local requirements in a timely
manner in the event of a failure or malfunction of the system installed.
C. Before a product development permit is issued, the Water Quality Control Division must
determine that the product to be tested qualifies for testing under the product development
evaluation based on information submitted to the Division.
1. Applicant must provide evidence of nationally accepted third -party testing of the product
to be evaluated, or
2. Provide test data from multiple single-family homes under normal working conditions that
meet the following criteria:
a. Test data must be provided from a minimum of four sites.
b. Each system must be tested over a period of at least one year.
c. Each system must be sampled at least three times during the year with at least one
sample obtained during cold weather conditions.
d. Laboratory results for all parameters for which acceptance is being requested must be
submitted.
D. The board of health must not arbitrarily deny any person the right to consideration of an
application for such a system and must apply reasonable performance standards in
determining whether to approve such an application; 25-10-108 (2), C.R.S.
E. A completed application for a product development permit must be submitted to the Division
at least 30 days in advance of installation of the product.
F. An application for a product development permit must include the following:
1. Proof of the ability to install a replacement OWTS in compliance with all local requirements
in a timely manner in the event of a failure or malfunction of the system under testing;
2. A description of the product under development including performance goals;
3. Documentation signed by the owner of the proposed product development site allowing
access to the local public health agency and Division for inspection of the site; and,
4. Design documents as required in section 30-5-70 of this regulation.
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G. Other than the performance standards identified in section 30-4-100 C. 2 above, the division
may stipulate additional requirements for the product development permit necessary to ensure
that the system performs as intended.
H. A product development permit is a site -specific permit. Product development testing at
multiple sites requires a product development permit for each site.
I. During the term of the product development permit, all data collected is to be submitted to the
Water Quality Control Division and the Division.
J. The Division may revoke or amend a product development permit, if the continued operation
or presence of the product under development:
1. Presents a risk to the public health or environment;
2. Causes adverse effects on the proper function of the OWTS on the site;
3. Leaks or discharges effluent on the surface of the ground; or
4. If the developer of the product fails to comply with any requirements stipulated on the
permit by the Division or the Water Quality Control Division.
K. If the product development permit is revoked, the product developer must install the
replacement system.
L. Once the system is installed and approved, the Division must supply the Water Quality Control
Division with a copy of the completed OWTS permit.
M. The Division prohibits the reduction of system size, or the reduction in vertical or horizontal
separation when higher level treatment systems are used.
Amend Sec. 30-4-110. Systems Contractor License.
A. No person, except as in Section 30-4-110.B below, shall install, engage in the installation of,
or repair an OWTS unless such person holds a valid systems contractor license issued by the
Division. Employees of a validly licensed Systems Contractor shall not be required to be
licensed. The initial fee for a systems contractor license shall be set by separate Chapter of
the Board of Weld County Commissioners. A license shall expire on December 31 of each
year, and shall be renewed within thirty (30) days prior thereto, and an annual renewal fee, as
set by separate Chapter of the Board of Weld County Commissioners, shall be charged. A
license which lapses because of failure to renew or is revoked shall be subject to the fee
established for a new license upon re -application.
Remainder of Section — No change.
Amend Sec. 30-4-130. Variance procedure.
A. and B. — No changes.
C. Variances for repair of failing systems.
1. — No change.
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2. For the repair of or upgrade to an existing system where the existing system does not
meet the required separation distances and where the conditions other than lot size
precludes adherence to the required distances, a variance to the separation distances
may be requested. The repairs or upgrade must be no closer to features requiring
setbacks than the existing facilities. Variances requesting setbacks no closer than
existing setbacks do not have to provide technical justification from a professional
engineer or professional geologist.
D. Prohibitions on the granting of variance requests.
1. and 2. — No change.
3. No variance will be issued which will result in setbacks to an offsite physical feature
which do not conform to the minimum setbacks defined in Table 30-7-1 without the board
of health considering any concerns of the owner of property containing said feature.
Property lines are considered offsite features. The property owner containing said
feature must be notified of the time and date of the hearing.
4. thru 6. — No change.
7. No variance shall be issued for the installation of a higher level treatment system based
on sizing or separation reductions.
Remainder of Section — No change.
Amend Sec. 30-4-140. General prohibitions.
A. — No change.
B. Use, construction or existence of cesspools, pit privies, slit trenches, and seepage pits, is
prohibited.
Remainder of Section — No change.
Amend Sec. 30-4-160. Enforcement.
A. — No change.
B. Cease and desist orders. The Health Officer or his or her designee may issue an order to
cease and desist from the use of any OWTS or sewage treatment works which is found by
the Health Officer not to be functioning in compliance with these Regulations, the OWTS Act
or with applicable regulations, or is found to constitute a hazard to public health or has not
otherwise received timely repairs under the provisions of Section 25-10-106(1)(j), C.R.S.
Such an order may be issued only after a hearing which shall be conducted by the Health
Officer not less than forty-eight (48) hours after written notice thereof is given to the owner or
occupant of the property on which the system is located. The order shall require that the
owner or occupant bring the system into compliance or eliminate the health hazard within
thirty (30) days, or thereafter cease and desist from the use of the system. A cease and desist
order issued by the Health Officer shall be reviewable in the district court for the County
wherein the system is located and upon a petition filed not later than ten (10) days after the
order is issued.
Amend Sec. 30-4-170. Penalties.
A. and B. — No change.
C. Upon a finding by the local board of health that a person is in violation of this regulation, the
local board of health may assess a penalty of up to fifty dollars for each day of violation. In
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determining the amount of the penalty to be assessed, the local board of health shall consider
the seriousness of the danger to the health of the public caused by the violation, the duration
of the violation, and whether the person has previously been determined to have committed
a similar violation.
D. A person subject to a penalty assessed pursuant to section 30-4-170 B. may appeal the
penalty to the local board of health by requesting a hearing before the appropriate body. The
request must be filed within thirty days after the penalty assessment is issued. The local
board of health shall conduct a hearing upon the request in accordance with section 24-4-
105, C.R.S.
ARTICLE V - Site and Soil Evaluation
Amend Sec. 30-5-10. Site and soil evaluation general requirements.
A. A site and soil evaluation must be conducted for each property on which an OWTS is
proposed, to determine the suitability of a location to support an OWTS and to provide the
designer with a sound basis to select the most appropriate OWTS design for the location and
application. Each site evaluation must consist of:
1. Preliminary investigation;
2. Reconnaissance;
3. Detailed soil investigation; and
4. Report and site plan.
Amend Sec. 30-5-20. Preliminary investigation.
A. Preliminary investigation: Research of information relative to the site and anticipated
conditions must be conducted. Information gathered as part of the preliminary investigation must
include, but is not limited to:
1. Property information:
a. Address;
b. Legal description;
c. Existing structures; and
d. Location of existing or proposed wells on the property.
2. Existing Division OWTS records.
3. Published site information:
a. Topography; and
b. Soil data.
4. Location of physical features, on and off the property, that will require setbacks, as
identified in Table 30-7-1.
5. Preliminary soil treatment area size estimate based on information on existing or planned
facility and local regulations.
6. Other information required by the Division.
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7. Additional information that may be useful to the specific evaluation, as available:
a. Survey;
b. Easements;
c. Floodplain maps;
d. Geology and basin maps and descriptions;
e. Aerial photographs;
f. Climate information; and
g. Delineated wetlands maps.
Amend Sec. 30-5-30. Reconnaissance.
A. Reconnaissance: A visit to the property to evaluate the topography and other surface
conditions that will impact the location and design of the OWTS must be conducted.
Information gathered as part of the site reconnaissance may include, but is not limited to:
1. Landscape position;
2. Topography;
3. Vegetation;
4. Natural and cultural features; and
5. Current and historic land use.
Amend Sec. 30-5-40. Detailed soil investigation.
A. Soil investigations to determine the long-term acceptance rate of a soil treatment area must
be conducted per the following criteria:
1. Visual and tactile evaluation of two (2) or more soil profile test pit excavations must be
conducted to determine soil type as well as to determine whether a limiting layer is
encountered.
2. In addition to the two soil profile test pit excavations, percolation testing may be
conducted to obtain additional information regarding the long-term acceptance rate of
the soil.
3. If the site evaluation includes both a visual tactile evaluation of soil profile test pit
excavations and percolation tests, and the results from these two evaluations do not
coincide with the same LTAR as noted in Table 30-10-1, the designer must use the more
restrictive LTAR in determining the size of the soil treatment area.
B. Procedure for performing visual and tactile evaluations of soil in order to determine a long-
term acceptance rate:
1. The soils evaluation shall be performed by or under the supervision of a professional
engineer, professional geologist, competent technician, or other similarly qualified
professional as approved by the Division.
2. Evaluation of two (2) or more soil profile test pit excavations must be performed to
determine soil types, limiting layers, and best depth for the infiltrative surface. The total
number of soil profile test pit excavations beyond the required two shall be based on the
judgment of the competent tec hnician.
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3. At least one (1) of the soil profile test pit excavations must be performed in the portion of
the soil treatment area anticipated to have the most limiting conditions.
4. The minimum depth of the soil profile test pit excavation must be to any limiting layer, or
four feet below the infiltrative surface of the in -situ soil, whichever is encountered first.
5. Layers and interfaces that interfere with the treatment and dispersal of effluent must be
noted. Thus, any limiting soil characteristic such as consistence also needs to be
evaluated. The evaluation of consistence may also include an evaluation of excavation
difficulty, rupture resistance, and/or penetration resistance.
6. The soil observations must be conducted at or immediately adjacent to the location of
the proposed soil treatment area, but if possible, not under the final location of a trench
or bed.
7. Each soil profile test pit excavation observed at the proposed soil treatment area must
be evaluated under adequate light conditions with the soil in an unfrozen state.
8. The soil observation method must allow observation of the different soil horizons that
constitute the soil profile.
9. Soil profile test pit observations must be conducted prior to percolation tests to determine
whether the soils are suitable to warrant percolation tests and, if suitable, at what depth
percolation tests must be conducted.
10. The soil type at the proposed infiltrative surface of the soil treatment area or a more
restrictive soil type within the treatment depth must be used to determine the long-term
acceptance rate from Table 30-10-1 or Table 30-10-1A. The treatment depth is two to
four feet depending on the required thickness for the treatment level below the infiltrative
surface from Item 4, Table 30-7-2.
11. Soils data, previously collected by others at the site can be used for the purposes of an
OWTS design at the discretion of the local public health agency. It is recommended that
the data be verified, at a minimum, by performing an evaluation of a soil profile test pit
excavation.
C. Soil descriptions for determination of a limiting layer must include:
1. The depth of each soil horizon measured from the ground surface and a description of
the soil texture, and structure of each soil horizon;
2. Depth to the bedrock;
3. Depth to the periodically saturated soil as determined by:
a. Redoximorphic features and other indicators of water levels; or
b. Depth of standing water in the soil observation excavation, measured from the
ground surface, if observed, unless redoximorphic features indicate a higher level.
D. Procedure for performing percolation tests:
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1. — No change.
2. Number of test holes; Location.
a. Soil percolation tests shall be performed in at least three (3) test holes in the area
in which the soil treatment area is to be located, spaced evenly over the proposed
area.
b. If the likely depth of a proposed infiltrative surface is uncertain, percolation tests
must be performed at more than one (1) depth to determine the depth of the
infiltrative surface.
3. Dimensions.
a. The percolation test hole must have a diameter of eight (8) to twelve (12) inches and
be terminated a minimum of six (6) inches and a maximum of eighteen (18) inches
below the proposed infiltrative surface.
4. Change in soil.
a. If a change of soil type, color or structure is present within those soils comprising the
depth of soil below the infiltrative surface as required in Table 30-7-2 for vertical
separation, a minimum of two (2) soil percolation holes must be terminated in the
changed soil and percolation tests must be conducted in both holes.
5. Percolation tests.
a. The percolation tests must be conducted using the hole preparation, soil saturation
and rate measurement procedures described below.
b. — No change.
c. Presoak.
1) The hole must be presoaked adequately to accomplish both saturation, which
is filling the void spaces between the soil particles, and swelling, which is the
intrusion of water into the individual soil particles.
2) — No change.
d. Percolation rate measurement.
1) With the exception of sandy soils containing five percent (5%) or less particles
passing through the #200 sieve, by weight, percolation rate measurements
must be made on the day following the presoak procedure.
2) If water remains in the percolation test hole after the swelling period, adjust the
depth to approximately six (6) inches above the gravel in the bottom of the hole.
From a fixed reference point, measure the drop in water level over thirty -minute
intervals. The drops are used to calculate the percolation rate.
3) — No change.
e. Sandy soils.
1) In sandy soils or other soils in which the first six (6) inches of water seeps out
of the hole in less than thirty (30) minutes, after the twenty-four (24) hour
swelling period, the time interval between measurements must be ten (10)
minutes and the test conducted for one (1) hour. The drop that occurs during
the final ten (10) minutes must be used to calculate the percolation rate.
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2) If the soil is so sandy or coarse textured that it will not retain any water, then
the infiltration rate must be recorded as less than one (1) minute per inch.
f. Percolation rate determination and reporting.
1) The field percolation rate will be the average rate of the percolation rates
determined for all percolation test holes observed in the proposed soil treatment
area in minutes per inch. The average percolation rate determined by the tests
must be used in determining the long-term acceptance rate for the proposed
system from Table 30-10-1.
2) The technician performing the percolation tests shall furnish an accurate scale
drawing, showing the location of the soil profile test pit excavations and/or
percolation holes tied to lot corners or other permanent objects. The drawing
must meet the criteria in Paragraph 30-5-60.A.7. All holes must be clearly
labeled to relate to the information provided for the profile test pits and
percolation tests.
Alternate percolation testing.
1) Alternate percolation test procedures may be approved, provided that the test
results of alternate procedures are substantially equivalent to those determined
using the test procedures described in this Section.
2) Prior approval from the Division of alternate percolation test procedures is
required.
Delete E. and F. in its entirety.
Amend Sec. 30-5-50. Marking of Soil Profile Test Pit Excavations or Percolation holes.
The soil profile test pit excavations or percolation holes, must be flagged or otherwise marked
to allow easy location by others. Percolation holes must remain open until after evaluation by the
Division. The soil profile test pit excavations may be backfilled after evaluation by the third party
professional (professional engineer, geologist, competent technician or other similar
professional). If the profile test pit excavation is backfilled prior to inspection by the Division, a
monitoring port shall be installed prior to backfilling for evaluation by the Division. Soil test pit
excavations that are left open must be suitably barricaded to prevent unauthorized access and to
address safety concerns.
Amend Sec. 30-5-60. Report and site plan.
g.
A. A written report must describe the results of the preliminary investigation, reconnaissance
and detailed evaluations. The report may be in text and/or tabular form and must include a
drawing locating features relative to the proposed OWTS location and test locations. The
report may be included as part of the OWTS design document. The report must include, but
is not limited to:
1. Company name, address, telephone number, e-mail address and name of individual,
credentials and qualifications of the individual conducting the site evaluation;
2. Preliminary and detailed evaluations, providing information from the surface site
characteristics assessment and soils investigation;
3. Dates of preliminary and detailed evaluations;
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4. A graphic soil log, to scale, indicating depth of the soil test pit excavation, soil description
and classification, depth to any limiting layer encountered , type of equipment used to
excavate the soil profile test pit, and date of soils investigation;
5. Setback distances to features listed in Table 30-7-1;
6. Setback distances to features listed in Table 30-7-2, existing on the site or within
applicable setback limits, whichever is greater;
7. A drawing created to a scale that provides the complete property boundary lines. The
minimum drawing size is eight and one-half (8.5) inches by eleven (11) inches. If the
property is too large to adequately indicate and label the profile test pits and percolation
test holes, a detail of the portion of the site containing the soil profile test pits and
percolation test holes must be submitted. If the property is too large to adequately show
site evaluation information, a detail drawing that includes the information required from
the site and soil evaluation that will impact the location of the OWTS must be submitted.
Drawings must indicate dimensions, have a north arrow and graphic scale and include:
a. Fixed, non -degradable temporary or permanent benchmark, horizontal and vertical
reference points of the proposed soil treatment area; soil observations; percolation
testing results and pertinent distances from the proposed OWTS to all required
setbacks, lot improvements, easements, ordinary high water mark of a pond, creek,
stream, lake, wetland or other surface waters and detention or retention ponds; and
property lines;
b. Contours or slope direction and percent slope;
c. The location of any visible or known unsuitable, disturbed or compacted soils;
d. The estimated depth of periodically saturated soils and bedrock or flood elevation,
if applicable; and
e. The proposed elevation of the infiltrative surface of the soil treatment area, from an
established datum (either ground surface or a benchmark).
8. Anticipated construction -related issues, if applicable;
9. An assessment of how known or reasonably foreseeable land use changes are expected
to affect the system performance, including but not limited to changes in drainage
patterns, increased impervious surfaces and proximity of new water supply wells, if
applicable; and
10. A narrative explaining difficulties encountered during the site evaluation, including but
not limited to identifying and interpreting soil and landform features and how the
difficulties were resolved, if applicable.
Amend Sec. 30-5-70. Design document.
A. The report and site plan may be attached to the design document or the report and site plan
may be combined with the design information as a single document.
B. The design document must include a brief description of the facility and its proposed use,
basis and calculations of design flow and influent strength.
C. The design document must contain all plan detail necessary for permitting, installation and
maintenance, including:
1. Assumptions and calculations for each component, including total dynamic head (TDH)
and gallons per minute (GPM) for all dosing systems;
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II
2. A fixed, non -degradable temporary or permanent benchmark, (North America Vertical
Datum or assumed elevation is acceptable);
3. A scale drawing showing the location of each OWTS component and distances to water
supplies, surface water, physical and health impact features on both the subject and
adjacent properties requiring setbacks;
4. Layout of soil treatment area, dimensions of trenches or beds, distribution method and
equipment, distribution boxes, drop boxes, valves or other components used;
5. Elevation or depth of infiltrative surface of the soil treatment area, the septic tank invert,
and all other components of the OWTS;
6. Special structural design considerations, as applicable to ensure the long-term integrity
of each component;
7. References to design manuals or other technical materials used;
8. Installation procedures, as applicable;
9. Operation and maintenance manuals or instructions; and
10. Other information that may be useful, such as photos and cross-section drawings.
Amend Sec. 30-5-80. Site protection.
Prior to and during construction, the proposed soil treatment area and replacement area, if
any, must be protected from disturbance, compaction or other damage by means of staking,
fencing, posting or other effective method.
Amend Sec. 30-5-90. Qualifications for competent technician.
A. — No change.
B. Visual and tactile evaluation of soil.
1. Competencies needed:
a. and b. — No change.
c. Identify type and grade of soil structure;
d. thru g. — No change.
2. Possible demonstrations of competence in visual and tactile evaluation of soil:
a. — No change.
b. Attendance at training or workshop for soil evaluation for OWTS, including both class
and field work.
(1) If the training or workshop includes an exam to verify acceptable completion of
the course, a passing grade on the exam must be attained.
3. The Water Quality Control Division must approve training for visual and tactile evaluation
of soil.
ARTICLE VI - Wastewater Flow and Strength
Amend Sec. 30-6-10. Wastewater flows.
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A. — No change.
B. Single-family residential homes.
1. Design flow per person must be seventy-five (75) gallons per day (gpd).
2. The minimum design flow for a new home must be for a two -bedroom house, unless
otherwise noted in this regulation. The minimum design flow for the repair or replacement
of an OWTS of an existing one -bedroom home must be for one -bedroom, unless
bedrooms are added.
3. For homes up to and including three (3) bedrooms, the assumed number of persons per
bedroom is two (2) for design purposes.
4. For homes with more than three (3) bedrooms, the assumed number of persons is six
(6) persons (first three [3] bedrooms x two [2] persons per bedroom), plus one (1)
additional person for each bedroom more than three (3) bedrooms.
5. — No change.
Table 30-6-1 — No change.
C. Auxiliary buildings.
1. — No change.
2. If the flow from the auxiliary building is only generated by residents of the home, it will
be assumed that the OWTS for the home will be adequately sized to include the auxiliary
building if the flows are combined.
3. — No change.
4. If the auxiliary building has a separate OWTS, the facility must be sized on the basis of
Table 30-6-2 and a septic tank detention time of forty-eight (48) hours.
D. Multi -family and commercial on -site wastewater treatment systems.
1. Design flow values and strengths for multi -family and commercial systems must be
determined from:
a. Table 30-6-2; or
b. An analysis of flows and strengths from at least three (3) comparable facilities or from
the facility, if it is an existing facility, must be submitted to the Division for approval.
The analysis must include:
1) Metered water flows for inside use only for at least a year or, if the use is seasonal,
for a full season. If metered flows are less than full capacity, they must be paired
with actual use in units of persons present or meals served or other units as
appropriate so that an actual daily rate per unit can be determined. The daily rate
per unit times the number of units at full occupancy will be the design flow.
2) Total suspended solids and BOD 5 or CBOD 5 tests at times of full use. At least
three (3) samples, taken at least one (1) week apart, are required. Sampling that
provides equivalent and representative data through "composite sampling" may be
allowed.
3) Explanation and justification for the comparability of the tested facilities with the
proposed facility.
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E. Flow equalization.
1. — No change.
2. The highest peak assumed must be at least equal to the full capacity of the facility.
3. The stored flow must be distributed to the soil treatment area before the next greater -
than -average peak.
4. — No change.
5. Timed dosed pressure distribution or timed dosed NDDS must be used. The soil
treatment area reduction for pressure distribution must not be used in addition to the flow
equalization reduction.
6. — No change.
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Amend Table 30-6-2
Estimate of Average Daily Wastewater Flow and
BOD 5 Load Per Person Unless Otherwise Noted
BOD 5 in
GPD Pounds Per
Day
Residential Wastewater
Single-family dwellings
Auxiliary buildings by fixture type
Bath/shower
Dishwasher
Kitchen sink with garbage grinder
Laundry washer
Lavatory
Water closet (toilet)
14.7 .014
8.4
.021
Hotels and motels per room i 75
Multiple -family dwellings or apartments
Boarding and rooming houses (users absent during working hours) 50
Tiny Homes***, per unit
Mobile home
Mobile home park per space
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Commercial Wastewater
.15
150
.002
.40
75 i .20
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Facilities with short-term or transient visitors
Examples: Airports or bus stations per passenger; fairgrounds per
person attending; ball parks, race tracks, stadiums, theaters or
auditoriums per seat
Airport per employee
Barber and beauty shops per chair
Bowling alleys per lane - toilet wastes only
Country club per member
Country club per employee
Dentist offices per non -wet chair
Doctor offices per doctor
5 .02
10
100;
5
30
20
50
250
Factories and plants exclusive of industrial wastewater per employee 4 20
per eight -hour shift - no showers
Factories and plants exclusive of industrial wastewater per employee
per eight -hour shift - showers provided
Kennels per dog
Laundries, self-service per commercial washer 400 .75
Office buildings per employee per 8 -hour shift f 15 .06
Service stations per toilet fixture ; 250 .50
Stores and shopping centers per square foot of retail space
Work or construction camps semi -permanent with flush toilets
.06
.70
.03
.02
.06
.14 *
.80
.05
Work or construction camps semi -permanent without flush toilets 1 35
Food Service Establishment
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.08
.01
.17
.02
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Restaurant open 1 or 2 meals per seat
24 -hour restaurant per seat
Restaurant with paper service only per seat
Additional for bars and cocktail lounges per seat
Drive-in restaurant per car space
.06/meal
75 .07/meal served
25 i .01 /meal served
30
.02
50 .02
Institutional Wastewater Without Kitchens Unless Otherwise Noted
Churches, per seat; without any food service, or other uses
Churches, per seat; warming kitchen only, no major food service
Churches, per seat; with food service, per meal served****
Hospitals per bed space
Nursing homes; Group homes for developmentally disabled, per bed
space
Schools, boarding per person
Schools, day without cafeteria, gym or showers
Schools, day with cafeteria, no gym or showers
Schools, day with cafeteria, gym and showers
Schools, day additional for school workers
Recreational and Seasonal Wastewater Use
Camps, day, no meals served
Luxury resort
Resort, night and day
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13.5
250
.01
.01
.02
.20
125 .20
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Campground per campsite `*
Public park flush toilet per fixture per hour when park is open
Public park urinal per fixture per hour when park is open
Public park shower per fixture per hour when park is open
Public park faucet per fixture per hour when park is open 15
Swimming pools and bathhouses
Travel trailer parks with individual water and sewage hookup per unit 100
Travel trailer park without individual water and sewage hookup per
unit "
.04 lbs./fixture
.01 lbs/fixture
.10 lbs./fixture
.04 lbs./fixture
` BOD levels need further verification depending on the specific use of the facility.
{
** Laundry facilities are to be calculated on a per -commercial washer basis in accordance with
other elements of this table.
***For the purpose of this Table, a "Tiny home" is a structure that has only one bedroom and
has <400 sq.ft. of livable space, including lofts. In this instance, the OWTS may be sized for
only one bedroom.
****For churches with food service, the 4 gal/meal must be added to the 3.5 gal/seat to
determine projected design flows.
Amend Sec. 30-6-20. Wastewater strength.
A. — No change.
B. High strength waste must be reduced to at least Treatment Level TL1 quality or lower before
applying to a soil treatment area. Waste strength levels defined in Tables 30-6-3 and 30-6-4
must be used to determine compliance.
Amend Table 30-6-3
Treatment Levels
Treatment
Level
TL 1 2
TL 2
BOD5 (mg/L) CBOD51 (mg/L)
m /L Total Nitrogen
TSS
(mg/L) ) (mg/L)
80
60-80
N/A3
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> 50% reduction f
4
N/A3
TL3N = i 10 10
(Shading indicates higher treatment levels)
1 Requirements for CBOD5 are only related to effluent samples from a higher level treatment
system.
2 Domestic septic tank effluent prior to soil treatment or higher level treatment has a wide range
of concentrations. These values are typical, but values used for design must account for site
specific information.
3 Total Nitrogen does not apply to Treatment Levels TL2 and TL3. Processes intended to reduce
total nitrogen are addressed in Treatment Levels TL2N and TL3N. Any total nitrogen reductions
that may be observed for TL2 and TL3 are as a result of the treatment process for BOD5 and TSS
reductions.
4 NSF/ANSI Standard 245 - Wastewater Treatment Systems - Nitrogen Reduction requires
reduction of 50 percent rather than an absolute value.
Add Table 30-6-4 High Strength Wastewater*
BOD5 (mg/L)
TSS (mg/L)
Fats, Oils, Grease (FOG)
(mg/L)
Septic Tank Influent
>300
>200
>50
Septic Tank Effluent
>180
>80
>25
"High strength effluent prior to a septic tank has a wide range of concentrations. The values are typical, but
values used for design purposes must account for site -specific information.
ARTICLE VII - Minimum Distances Between Components of an On -Site Wastewater
Treatment System and Physical Features
Amend Sec. 30-7-20. Dry gulches, cut banks and fill areas.
A. Separation distances to dry gulches, cut banks and fill areas in Table 30-7-1 must apply
unless the designer or design engineer determines, by observation of the exposed slope of
the dry gulch or cut bank or by soil profile test pit excavations, that a limiting layer is present
that will direct or allow the effluent from the soil treatment area to move laterally and surface.
In this instance, a greater distance may be required.
B. — No change.
C. The separation distance between a component and the crest of a dry gulch or cut bank will
be evaluated for potential erosion or slope instability if the components and the slope are too
close together. If there is potential for erosion or instability, the separation distance must be
increased until the risk is minimized.
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Amend Sec. 30-7-30. - On -site Wastewater Treatment System design consideration and
treatment requirements - separation distances from soil treatment area.
A. and B. — No change.
C. Item 4 in Table 30-7-2 addresses the required vertical separation distance between the
infiltrative surface of the soil treatment area and the limiting layer or the required depth of soil
comprising the soil treatment area.
Amend Table 30-7-1
Minimum Horizontal Distances in Feet Between Components of an On -Site Wastewater
Treatment System
Installed After November 15, 1973 and Water, Physical and Health Impact Features
Component
Septic Tank, Higher
Level Treatment Unit, I
Dosing Tank, Vault or
Vault Privy
Building Sewer or
Effluent Lines
STA Trench, STA Bed,
Unlined Sand Filter,
Subsurface Dispersal
System
Lined Sand Filter
Lined
Evapotranspiration
Field or Outside of
Berm of Lined
Wastewater Pond
Unlined Sand Filter in
Soil With a Percolation
Rate Slower than 60
Minutes per Inch,
Unlined or Partially
Lined
Evapotranspiration
System, Outside of
Berm of Unlined
Wastewater Pond, or
System Not Relying on
Spring,
Well,'
Suction
Line
Potable
Water
Supply
Cistern°
100
Potable Structure
Water . w/basement
Supply ` crawlspace or
Line2 footing drains
25 2
100 25 2
20
15
15
15
Structure
without
basement
crawlspace or
footing drains
10
15
15
10
25
25
15
10
Lines,
Piped or
Lined
Irrigation
Ditch
upslope
curtain
drain
Property I Subsurface
Drain,
Intermittent'
Irrigation
Lateral,
Drywall,
Storm water
Structure
Dry
Lake, Gulch,
Watercourse, Cut Septic
Irrigation Bank, ' Tank Higher level
Ditch, Fill treatment unit Dosing
Stream, Area Tank Vault or Privy
Wetland (from
Crest)
5
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STA for Treatment
Other than Aerosol
System Not Relying on
STA for Dispersal
1003 102 125 125 10 0 253 10 10
NOTE: The minimum distances shown above must be maintained between the OWTS
components and the features described. Where soil, geological or other conditions warrant,
greater distances may be required by the Board of Public Health or by the Water Quality
Control Commission pursuant to Section 25-8-206, C.R.S., and applicable regulations. For
repair or upgrading of existing OWTS where the size of lot precludes adherence to these
distances, a repaired OWTS shall not be closer to setback features than the existing OWTS,
as reviewed and approved by the Water Quality Control Division. Components that are not
watertight should not extend into areas of the root system of nearby trees.
1 Includes potable wells, irrigation wells and monitoring wells set within a potable aquifer
and infiltration galleries permitted as wells by the Division of Water Resources.
2 Crossings or encroachments may be permitted at the points as noted above, provided
that the water or wastewater conveyance pipe is encased for the minimum setback distance
on each side of the crossing. A length of pipe with a minimum Schedule 40 rating of sufficient
diameter to easily slide over and completely encase the conveyance must be used. Rigid end
caps of at least Schedule 40 rating must be glued or secured in a watertight fashion to the
ends of the encasement pipe. A hole of sufficient size to accommodate the pipe must be
drilled in the lowest section of the rigid cap so that the conveyance pipe rests on the bottom
of the encasement pipe. The area in which the pipe passes through the end caps must be
sealed with an approved underground sealant compatible with the piping used. Other
methods of encasement that provide equal protection are allowed. These methods must be
designed by a professional engineer and approved by the local public health agency.
3 Add 8 feet additional distance for each 100 gallons per day of design flows between 1,000
and 2,000 gallons per day, unless it can be demonstrated by a professional engineer or
geologist by a hydrologic analysis or the use of a barrier, consisting of a minimum 30 mil PVC
liner or equivalent, that contamination will be minimized.
4 All horizontal setbacks to a potable water supply cistern must be met unless a variance
by the Board of Examiners of Water Well Construction and Plumb Installation Contractors
is granted per section 11.4 of the Water Well Construction Rules, 2 CCR 402-2. The
minimum horizontal setback that may be granted through a variance is to 25 feet.
5 If the structure is not used as a habitable unit, the isolation may be reduced by the local
board of health to no less than 50 feet.
6 Building sewer installations shall meet the design requirements of the Colorado Plumbing
Code.
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Amend Table 30-7-2
On -site Wastewater Treatment System Design Consideration and Treatment
Requirements - Separation Distances from Soil Treatment Area
Item
1
2
OWTS Design Consideration
Horizontal Separation Distances
Distance from soil treatment area to on -site well
Distance from soil treatment area to pond, creek, lake or ; Greater than or equal to
other surface water feature
All Treatment Levels
Greater than or equal to
100 feet
50 feet
Greater than or equal to
3 Distance from soil treatment area to dry gulch or cut bank 25 feet
Vertical Separation Distances
Treatment depth in feet from infiltrative surface to a limiting I4 feet (3 feet with pressure
layer r dosing)
NOTE: Treatment levels are defined in Table 30-6-3.
ARTICLE VIII - Design Criteria - General
Amend Sec. 30-8-10. Performance.
A. The OWTS for single-family homes shall be designed to accommodate the proposed flows
from the structure as defined in 30-6-10.B. Flow estimates for multi -family or commercial
OWTS must comply with 30-6-10.D.1. Expected waste strength as noted in Table 30-6-3 and
Table 30-6-4 must also be addressed, where applicable. Installation of low flow fixtures or the
separation of toilet waste or other sources of wastewater does not allow for the reduction in
the size of an OWTS.
B. OWTS shall be designed and constructed to achieve the treatment level specified by the
design.
Amend Sec. 30-8-20. Reliability.
OWTS must be designed and constructed such that each component shall function, when
installed and operated, in a manner not adversely affected by normal operating conditions,
including erosion, corrosion, vibration, shock, climatic conditions and usual household chemicals.
Each component must be free of nonfunctional protrusions or sharp edges or other hazards,
which could cause injury to persons, animals or properties. Design must be such as to exclude
flies and rodents and other vectors and to prevent the creation of nuisances and public health
hazards and must provide for efficient operation and maintenance.
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Amend Sec. 30-8-30. Accessibility for inspection, maintenance and servicing.
A. Septic tanks must have watertight risers over each access manhole, and all risers must extend
to or above final grade.
B. For new construction, the top of any septic tank, dosing tank or vault must be no deeper than
four feet below finished grade.
C. Each treatment component of an OWTS, other than the septic tank and soil treatment area,
shall be equipped with access manholes with risers that extend to or above final grade, located
to permit periodic physical inspection, collection and testing of samples and maintenance of
all components and compartments.
D. Riser lids.
1. Each riser lid must be watertight, brought to or above the surface, and must have a secure
closing mechanism, such as a lock, special -headed bolts or screws, or sufficient weight
(defined as 59 pounds) to prevent unauthorized access.
E. Components that require access for maintenance must include, but not be limited to,
submerged bearings, moving parts, pumps, siphons, valves, tubes, intakes, slots, distribution
boxes, drop boxes, cleanouts, effluent screens, filters, inlet and outlet baffles, aerators,
treatment equipment and other devices.
F. Components must be designed and constructed so that, when installed, they must be easily
maintained, sampled and serviced according to the manufacturer's recommendations. Easy
physical access to treatment components by maintenance personnel and equipment must
be provided.
Amend Sec. 30-8-40. Plumbing codes.
Plumbing fixtures, building sewers, vents, sewer lines and other appurtenances must be
designed, operated and maintained so as to comply with the minimum requirements of the locally
enforced plumbing code. In the absence of a local plumbing code, designs must adhere to the
Colorado Plumbing Code (3 CCR 720-1). A local plumbing permit may be required.
Amend Sec. 30-8-50. Electrical equipment.
A. All electrical work, equipment and materials must comply with the requirements of the locally
enforced code. A local electrical permit may be required.
B. Electrical components must be protected from moisture and corrosive gases.
Amend Sec. 30-8-60. Indicators of failure or malfunctioning for systems utilizing
mechanical apparatus.
A signal device must be installed which will provide a recognizable indication or warning to
the user that the system or component is not operating as intended. This indication or warning
must be a visual signal and audible signal, and must be located in a centralized area within visual
and audible range of the system user. A signal or message may also be sent remotely to a
maintenance provider.
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Amend Sec. 30-8-70. Sampling access.
A. If sampling for testing or as a requirement for a permit will be required of effluent from a
component other than the soil treatment area, an accessible sampling point must be
provided.
B. If sampling of the treated wastewater from the soil treatment area will be required for testing
or as a requirement for a permit, a monitoring well or wells must be constructed. Monitoring
wells must be located down gradient from the soil treatment area, accessible and provided
with a properly securable cover at or above the ground surface. Monitoring wells up gradient
of the system may also be required. Lysimeters or other collection devices under the soil
treatment area may be used instead of a monitoring well.
Amend Sec. 30-8-80. Component operating instructions.
A. The manufacturer of proprietary treatment units utilizing mechanical components must
provide clear, concise written instructions covering the components which, when followed,
must assure proper installation and safe and satisfactory operation and maintenance.
B. If the OWTS uses public domain technology, the design engineer must provide clear, concise
written instruction covering the components which, when followed, must assure proper
installation and safe and satisfactory operation and maintenance.
Amend Sec. 30-8-90. Surface activity.
Activity or use on the surface of the ground over any part of the OWTS must be restricted.
The soil treatment area must not be subject to damage or soil compaction from livestock, vehicular
traffic, recreational use, or other site development activity. Construction equipment not necessary
to install the OWTS must be kept off of the soil treatment area to prevent undesirable compaction
of the soils. If compaction occurs, the disturbed or compacted soil must be reevaluated and/or
new soil evaluations performed. The system must be redesigned if the soil permeability has
changed.
Amend Sec. 30-8-100. Floodplains.
A. A new, expanded or repair/replacement OWTS installed in a 100 -year floodplain must meet
or exceed the requirements of the Weld County Floodplain Management Ordinance
contained in Chapter 23 and the Federal Emergency Management Agency. Repairs of an
existing system must meet the requirements as feasible. The system, as approved by the
Division, must be designed to minimize or eliminate infiltration of floodwaters into the system
and discharge from the system into the floodwaters. The OWTS must be located to avoid
impairment to floodwaters or contamination from them during flooding. The Division has
available a floodplain guidance document.
B. A new or expanded OWTS must not be installed in a floodway designated in a 100 -year
floodplain where a conforming OWTS outside the floodway can be installed. For any new
OWTS or system repair that may affect the floodway delineation, appropriate procedures
must be followed, including revision of the floodway designation, if necessary.
Amend Sec. 30-8-110. Business, commercial, industrial, institutional or multi -family
dwelling wastewater systems.
A. An OWTS that will serve a business, commercial, industrial or institutional property or a
multi -family dwelling must:
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1. Be designed by a professional engineer;
2. Receive only such biodegradable wastes for treatment and distribution as are compatible
with those biological treatment processes as occur within the septic tank, any additional
treatment unit and the soil treatment area; and
3. Receive authorization by rule or a Class V underground injection permit from the United
States Environmental Protection Agency (EPA) before an application for an OWTS
permit is approved, if the system may receive nonresidential wastewater or is otherwise
covered by the EPA underground injection control program. Subsequent to acceptance
by the EPA, the Division may choose to also issue a permit for this type of use.
ARTICLE IX - Design Criteria - Components
Amend Sec. 30-9-10. Tanks and vaults.
A. Watertightness.
1. Septic tanks, vaults, dosing tanks, other treatment components, risers and lids must not
allow infiltration of groundwater or surface water and must not allow the release of
wastewater or liquids through other than designed openings.
2. When the final compartment of a tank is being proposed for use as a pump or siphon
chamber, the wall between this chamber and the previous chamber must be watertight
except for the intended hydraulic opening.
3. Acceptable watertightness testing methods, performed at a manufacturer's site or in the
field, include water filling the tank or vacuum testing.
B. Tank anchoring. In locations where groundwater or floodwaters may cause instability
problems to the septic tank, vault or other treatment unit in the OWTS due to flotation, the
tank, vault or unit must be anchored in a manner sufficient to provide stability when the tank
is empty. Risers must be included in the buoyancy calculations.
1. If a manufacturer provides recommendations for anchoring designs, they may be used
if they meet the conditions present at the site.
2. If a manufacturer does not provide recommendations for provisions to compensate for
buoyancy or if the professional engineer chooses to provide his or her own designs, the
anchoring system design must be prepared by the professional engineer.
C. Identification and data marking. All tanks and treatment units must be permanently and
legibly marked in a location, for the purpose of inspection, that is readily visible when
inspected before backfilling. The marking inscription must include the following:
1. thru 5. — No change.
Amend Sec. 30-9-20. Septic tanks.
A. The manufacturer must provide sufficient information to demonstrate that the tank will meet
the design specification.
B. Sizing requirements:
1. Sizing for residential capacity for new installations must be based upon the number of
bedrooms according to Table 30-9-1:
Table 30-9-1 — No change.
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2. For multi -family and nonresidential applications, a septic tank must be sized to permit
detention of incoming wastewater design flows for a minimum of forty-eight (48) hours.
3. and 4. — No change.
C. Inspection and Testing of septic tank watertightness.
1. Testing of septic tanks must be performed and evaluated as specified in Section 9 of
ASTM C1227-13 (Standard Specification for Precast Septic Tanks) for concrete tanks or
in Standard IAPMO/ANSI Z1000-2013 (American Standards for Prefabricated Septic
Tanks) for other prefabricated septic tanks.
2. Each unit must be inspected in the field for conditions that may compromise its
watertightness.
3. The inspection in the field must be conducted by the Division and be performed after the
tank installation but before backfilling.
4. — No change.
D. Septic tank design and dimension criteria.
1. A septic tank must have two (2) or more compartments or more than one (1) tank may
be used in a series. The first compartment of a two -compartment tank or the first tank in
a series must hold no less than one-half (%) of the required effective volume.
2. Inlet invert must be at least two (2) inches higher than the outlet invert.
3. Inlet tee or baffle must extend above the surface of the liquid at least five (5) inches and
must extend a minimum of eight (8) inches below the liquid surface. However, the inlet
tee or baffle must not extend to a depth of more than 40 percent of the liquid depth
measured from the liquid surface.
4. Outlet tee or baffle must extend at least five (5) inches above and fourteen (14) inches
below the outlet invert, however, it must not extend to more than 40 percent of the liquid
depth measured from the liquid surface. The outlet tee or baffle that accommodates an
effluent screen must be located so that the effluent screen has sufficient clearance to be
removed through the access opening with a riser in place.
5. The distance from the outlet invert to the underside of the tank top must be at least ten
(10) inches.
6. Liquid depth must be a minimum of thirty (30) inches and the maximum depth must not
exceed the tank length.
7. The transfer of liquid from the first compartment to the second or successive
compartment must be made at a liquid depth of between thirty-five percent (35%) and
forty-five percent (45%) of the liquid depth measured from the liquid surface.
8. At least one (1) access opening no less than twenty (20) inches across must be provided
in each compartment of a septic tank.
9. A septic tank must have a minimum of twenty-five (25) square feet of liquid surface area
and have at least a six-foot separation between inlets and outlets. Septic tanks in series,
combined, must have a minimum of twenty-five (25) square feet of liquid surface area
and the sum of the distances between inlets and outlets of all tanks must be at least six
(6) feet. The requirements for liquid surface area and separation between inlet and outlet
may be waived for tanks with less than seven -hundred -fifty -gallon effective volume.
E. Concrete septic tank structural design.
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1. Concrete septic tanks must comply with the structural design criteria of ASTM C1227-
13 (Standard Specification for Precast Septic Tanks).
2. and 3. — No change.
4. Tank slab lids, mid -seam tanks, and the connections between the tank and risers must
be designed to provide for a watertight seal.
F. Fiberglass, fiberglass -reinforced polyester and plastic tanks.
1. All fiberglass, fiberglass -reinforced polyester and plastic tanks must meet the minimum
design and structural criteria of IAPMO/ANSI Z1000-2013 (American Standards for
Prefabricated Septic Tanks) and be certified by a professional engineer as meeting these
standards. The professional engineer certifying the criteria must be registered or
licensed in the United States but need not be registered in Colorado.
2. All tanks must be sold and delivered by the manufacturer or manufacturer's designated
representative, preferably completely assembled. On -site tank assembly will be allowed
on an as -needed basis.
3. Tanks must be structurally sound and support external forces, as specified in the
standard referenced above, when empty, and internal forces when full. Tanks must not
deform or creep, resulting in deflection of more than five percent (5%) in shape as a
result of loads imposed.
4. All tanks must be constructed of sound, durable materials and not be subject to
excessive corrosion, decay, frost damage or cracking.
5. All seams or connections, including to risers, must be sealed to be watertight.
G. Metal tanks are prohibited.
Amend Sec. 30-9-30. Abandonment of tank.
A. The contents of a tank shall be pumped by a County licensed systems cleaner and properly
disposed by methods specified in Section 30-4-120.B.3.
B. — No change.
C. If the tank will remain in place. (see Subsection A. above):
1. The bottom of the tank must be broken so that the tank neither floats nor fills with water;
2. — No change.
3. The remaining void must be filled with gravel, sand or compacted soil; and
Remainder of Section - No change.
Amend Sec. 30-9-40. Pipe standards and bedding requirements.
A. Pipe standards.
1. All wastewater pipes used in portions of an OWTS that are pressurized must be
constructed of compatible pipe, primer, bonding agent and fittings. Flexible couplings to
connect pipes may only be used in portions of an OWTS that are intended for gravity
flow of the wastewater.
2. Where unperforated plastic pipe and fittings are used for gravity flow, the minimum wall
thickness of the pipe must conform to ASTM Standard D 3034 or equivalent or greater
strength. Schedule 40 pipe is preferred.
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3. Perforated distribution pipe surrounded by rock within a soil treatment area must have a
minimum wall thickness and perforations conforming to ASTM Standard D 2729 or
equivalent or greater strength. Corrugated polyethylene pipe with smooth interior that
meets ASTM F405 or AASHTO M252 specifications or equivalent may be used.
4. Schedule 40 or pipe of equivalent or greater strength must be used for the placement of
piping under driveways or roadways and in instances where sewer line setback
distances are granted a variance for any reason.
5. and 6. — No change.
B. Bedding. All system piping, except for distribution laterals within the soil treatment area, must
be bedded with select material before final inspection by the Division. Select bedding material
must consist of loose, granular material free from stones, clods, frozen soil or other
deleterious material. Select material may consist of on -site job -excavated or imported
material. Bedding material must be mechanically compacted to support piping.
Remainder of Section — No change.
Add Section 30-9-50. Cleanouts.
A. Cleanouts required between the building and the septic tank:
1. Cleanouts must have a secure cap and a riser extending to or easily accessible from
grade. The installation of a straight tee or sanitary tee is acceptable.
2. Cleanouts must be provided within five (5) feet of the outside of the building.
3. Where a sewer has a change of horizontal direction greater than 45 degrees, a cleanout
must be installed at the change of direction unless a cleanout already exists within 40 feet
upstream of this fitting. Where more than one change of direction greater than 45 degrees
occurs within 40 feet of a developed length of piping, the cleanout for the first change of
direction may serve as the cleanout for all changes within that 40 feet of developed length
of pipe.
4. Cleanouts must be provided at intervals within the building sewer from the structure to the
tank of not more than 100 feet. The effluent pipe between the septic tank and soil treatment
area is exempt from this requirement.
Amend Sec. 30-9-60. Distribution box.
A. A distribution box, if used, must be of sufficient size to distribute effluent equally to the laterals
of a trench or absorption bed system. The box must be constructed with the inlet invert at
least one (1) inch above the level of the outlet inverts. Flow equalizers or similar devices must
be used to adjust the flow between laterals. Access to the box must be provided with a
manhole riser with access lid at or above grade if the top of the box does not reach final grade.
1. Each lateral shall be connected separately to the distribution box.
2. The distribution box shall be watertight and all pipes shall be grouted or cemented. The
box shall be located a minimum of five (5) feet from the septic tank.
3. The distribution box must be located outside of the absorption area. Solid wall pipe must
be installed from the distribution box until the beginning of the absorption area.
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4. In the event that treatment tank effluent is discharged to the distribution box by a pump,
a baffle shall be installed in the distribution box. The baffle shall be secured to the bottom
of the box, extending vertically to a point level with the crown of the inlet pipe and shall
be perpendicular to the inlet. In lieu of a baffle, the inlet pipe may have a ninety -degree
bend which diverts effluent downwards into the distribution box.
Amend Sec. 30-9-70. Drop box.
In sequential or serial distribution, a watertight box may be used to transfer the effluent to the
following trench when the effluent in a trench has received the designed level for overflow to the
next trench. A drop box shall have a riser at or above final grade if the top of the box does not
reach final grade. Outlet pipes in a sequential distribution must be designed and installed so that
they may be capped off for resting periods.
Amend Sec. 30-9-80. Stepdown/relief Pipe.
In sequential or serial distribution, an unperforated pipe may be used to transfer the effluent
to the following trench when the effluent in a trench has received the designed level for overflow
from that trench.
Amend Sec. 30-9-90. Wastewater pumping and dosing siphon systems.
A. Pumps.
1. Non -clog pump opening must have at least two-inch diameter solids handling capacity
where raw wastewater is pumped. A pump opening must not have more than three -
fourths -inch diameter solids handling capacity if previously settled effluent is pumped.
2. and 3. — No change.
B. Floats and switches.
1. — No change.
2. Floats must be mounted on a stem separate from the pump discharge piping to allow for
removal, adjustment and replacement of the float from grade without removing the pump.
3. — No change.
4. Dosing siphons for pressure dosing and higher level treatment systems must provide for
a means of determining the number of dosing events.
C. Location of pump or siphon.
1. A pump or a siphon may be, installed in a separate tank following the septic tank. The
tank must be of sufficient volume to allow pump or siphon cycling commensurate with
the design capacity.
2. The second compartment of a two -compartment septic tank may only be used as the
pump tank when the tank is specifically designed for this purpose and it can be
demonstrated, to the satisfaction of the Division, that the minimum forty -eight -hour
detention time will not be decreased. The pump must be screened or provided with an
approved filtering device to assure that only liquid effluent will be discharged. The transfer
of liquid from the first to the second compartment must be at an elevation that is between
the inlet and outlet invert elevations, and through a standard tee designed and located
as per the requirements of section 30-9-20.D.4. Siphons must not be installed in the
second compartment of a two compartment tank.
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3. The use of a three -compartment septic tank, sized to provide the required effective
volume in the first two compartments with the pump or siphon in the third compartment
is acceptable for tanks specifically designed for this purpose. The transfer of liquid from
the second to the third compartment must be at an elevation that is between the inlet and
outlet invert elevation, and through a standard tee designed and located as per the
requirements of section 30-9-20.D.4.
D. Pump or siphon discharge piping.
1. The discharge pipe from the pumping or siphon chamber must be protected from
freezing by burying the pipe below frost level or sloping the pipe to allow it to be self -
draining. Drainage must be provided through the bottom of the pump or through a weep
hole located in the discharge pipe prior to exiting the tank.
2. The pump discharge piping must have a quick disconnect that is accessible from grade
to allow for easy pump access and removal.
3. The pipe must be sized to maintain a velocity of two (2) or more feet per second.
4. Pressure pipes must be designed to prevent air or vacuum locking and allow self draining
of the pipes.
E. Access.
1. The pump or dosing system tank, chamber or compartment must have a minimum
twenty -four -inch diameter access riser, made of corrosion -resistant material, extending
to or above ground level. A smaller diameter riser may only be installed if it is accepted
by the Water Quality Control Division as an integral component of a specific product
during the product review process.
2. The access riser must have a watertight connection to the pump or dosing
chamber/compartment to prevent infiltration or exfiltration. All other intrusions to the riser
for electrical or other component access must also be watertight.
F. Splice box.
1. Splice boxes must be located outside the pump system access riser and be accessible
from the ground surface.
2. Wire splices are prohibited inside the tank, dosing chamber or riser. Wire splicing must
be completed with corrosion -resistant, watertight connectors.
G. Controls.
1. Control panels or other electrical boxes used to control the functions of an OWTS must
comply with the following, as appropriate:
a. The pump system must have an audible and visual alarm notification in the event an
excessively high water condition occurs.
b. The pump must be connected to a control breaker separate from the high water
alarm breaker and from any other control system circuits. An electrical disconnect
must be provided within the line of sight of the pump chamber.
c. The pump system must be provided with a means that will allow the pump to be
manually operated.
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d. The pump system for pressure dosing and higher level treatment systems must have
a mechanism for tracking both the amount of time the pump runs and the number of
cycles the pump operates.
e. Must bear the seal of a Nationally Recognized Testing Laboratory (NRTL), such as
UL or ETL.
Amend Sec. 30-9-100. Effluent screens.
A. If a pump or dosing siphon is used to remove septic tank effluent from the final compartment
of the septic tank, the effluent must be filtered prior to dispersal into the soil treatment area.
An effluent screen, pump vault equipped with a filter cartridge, or a filter on the discharge
pipe, would all be considered acceptable.
B. The effluent screen, if used, must be cleaned at manufacturer -recommended intervals or
more often, if use patterns indicate.
C. An alarm may be installed on an effluent screen indicating need for maintenance.
D. Where an ejector pump, grinder pump or non -clog pump is proposed for use prior to the
septic tank, an effluent screen must be installed on the outlet of the septic tank.
E. The handle of the effluent screen must extend to within 12 inches of grade.
Amend Sec. 30-9-110. Grease interceptor tanks.
A. and B. — No change.
C. The grease interceptor must have a minimum of two compartments and must be sized
proportionate to the amount of fats, oils and grease it receives, the peak flow rate through
the tank, and the expected cleaning frequency.
D. The inlet and outlet tees or baffles must extend into the bottom 1/3 of the liquid volume, but
must be at least 12 inches off the inside floor of the interceptor.
E. The inlet and outlet tees or baffles must extend at least 5 inches above the liquid level and
must provide for a free vent area across the liquid surface.
ARTICLE X - Design Criteria - Soil Treatment Area
Amend Sec. 30-10-10. — Soil Treatment Area General.
A. The size and design of the soil treatment area must be based on the results of the site and
soil evaluation, design criteria and construction standards for the proposed site and OWTS
selected.
B. At proposed soil treatment area locations where any of the following conditions are present,
the system must be designed by a professional engineer and approved by the Division:
1. For soil types, 3A, 4, 4A, 5, R-0, R-1 and R-2, as specified in Table 30-10-1 and 30-10-
1A of this Regulation;
2. The maximum seasonal level of the groundwater surface is less than four (4) feet below
the bottom of the proposed infiltrative surface;
3. A limiting layer exists less than four (4) feet below the bottom of the proposed infiltrative
surface;
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4. The ground slope is in excess of thirty percent (30%); or
5. Pressure distribution is used.
Amend Sec. 30-10-20. Calculation of infiltrative surface of soil treatment area.
A. — No change.
B. Long-term acceptance rates (LTARs) are shown in Table 30-10-1 and 30-10-1A.
C. — No change.
D. The required area for a soil treatment area is determined by the following formula:
Soil treatment area in feet required = Design flow (in gallons per day)
LTAR (in gallons per day per square foot)
1. and 2. — No change.
3. Size adjustment factors for types of distribution media are in Table 30-10-3.
4. and 5. — No change.
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Amend Table 30-10-1
Soil Treatment Area Long -Term Acceptance Rates by Soil Texture, Soil Structure,
Percolation Rate and Treatment Level
Soil Type
R
Soil Type, Texture, Structure and Percolation Rate Range
1
USDA Soil Texture
>35% Rock (>2mm):
See Table 30-10-1A
USDA Soil USDA Soil ! Percolation Rate
Structure - Type Structure - Grade : (MPI)
>35% Rock
(>2mm): See Table
30-10-1A
Long -Term Acceptance Rate
(LTAR); Gallons per day per
square foot
All Treatment Levels
>35% Rock >35% Rock >35% Rock (>2mm). See Table
(>2mm): See Table (>2mm): See Table 30-10-1A
30-10-1A 30-10-1A
Sand, Loamy Sand Single Grain 0 (Structureless)
PR
2 Sandy Loam, Loam, Block GR
Silt Loam (Blocky) ) BK
2A
Sandy Loam, Loam,
Silt Loam
Sandy Clay Loam,
3 Clay Loam, Silty Clay PR, BK, GR
Loam
(Granular)
PR, BK, GR
Massive
Sandy Clay Loam,
3A Clay Loam, Silty Clay
Loam
4
4A
5
Sandy Clay, Clay,
Silty Clay
PR, BK, GR
Massive
PR, BK, GR
Sandy Clay, Clay, PR, BK, GR
Silty Clay Massive
Soil Types 2-4A
Platy
1
2 (Moderate)
3 (Strong)
1 (Weak)
0 (Structureless)
2, 3
1
0 (Structureless)
2, 3
0 (Structureless)
1,2,3
61-75
0.30
Shaded areas require system design by a professional engineer.
'Treatment levels are defined in Table 30-6-3.
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5-15
26-40
41-60
76-90
121+
0.80
0.60
0.50
0.35
0.15
0.10
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Add Table 30-10-1A Design Criteria for Soils with High Rock Content (Type "R" Soils) 1'2'3'4
Soil Type, Percentage of Rock, LTAR, Distribution
Required Sand or
Media Depth Relative
to the Quality of
Effluent Applied to the
Distribution System
Soil Type
Percentage and
Size of Rocks
Maximum LTAR
(qal/sq ft/day
Type of Distribtion
Required
Treatment Level 16
R-0
Soil Types 1 with
more than 35%
Rock (>2mm)
Unlined Sand Filter:
1.0 for "Preferred
Sand Media:, 0.8 for
"Secondary Sand
Media"
Pressure
Distsribution6
Minimum 3 -foot
deep Unlined Sand
Filter
R-1; Option 1
Soil Type7 2-5,
>35%-65% Rock
(>2mm); With >50%
of the Rock <20 mm
(3/4 inch)
Use TL1 LTAR from
Table 30-10-1 for the
soil type
corresponding to the
soil matrix with a
maximum LTAR of
0.8
Pressure
Distributions
Minimum 2 -foot
deep Unlined Sand
Filter
R-1; Option 2
Soil Type 2 and 2A,
>35%-65% Rock
(>2mm); With >50%
of the Rock <20 mm
(3/4 inch)
The allowable LTAR's
are defined in each
individual treatment
level column in this
table
Pressure
Distributions
Remove, mix,
replace 4 feet of
existing material;
with a maximum
LTAR
R-2
Soil Type 2-5,
>65% Rock (>2mm),
OR >50% of Rock
>20mm (3/4 inch)
Use TL1 LTAR from
Table 30-10-1 for the
soil type
corresponding to the
soil matrix, with a
maximum LTAR of
0.8
Timed,
Pressure
Distributions'
Minimum 3 -foot
deep Unlined Sand
Filter
1. General guidance for Table 30-10-1A: The intent of the soil type R-0 is
high percentage of rock, or rock fragments, and has a percolation rate
R-2 consist of a high percentage of rock or rock fragments, but have a
Soil types R-0 and R-2 are considered to be a "limiting layer".
to define a material that consists of a
of less than 5 mpi. Soil types R-1 and
percolation rate of greater than 5 mpi.
2. No sizing adjustments are allowed for systems placed in type "R" soils. The maximum LTAR's are provided
in this table
3. The design of type "R" soil treatment systems must conform to sections 30-11-30.B and C.
4. All systems installed in a type "R" soil must be designed by a professional engineer.
5. The percentage of rock may be determined by a gradation conducted per ASTM standards, or an
appropriate field evaluation by volume.
6. Type "R" soil treatment systems that are designed per the criteria noted in the Treatment Level 1 column of
this table do not require O/M oversight by the LPHA.
7. The "Percentage and Size of Rock" column references the soil types noted in Table 30-10-1.
8. Design of the pressure distribution system for type "R" soils shall comply with the requirements of sections 30-
11-30 B. 2. a, b, c, d, and e.
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Amend Sec. 30-10-30. Allowable soil treatment area Sizing Adjustments.
A. The soil treatment area size, determined by dividing the design flow rate by the long-term
acceptance rate, may be adjusted by factors for soil treatment area design and type of
distribution media.
B. For the purpose of the table, a "baseline system," i.e., adjustment factor of 1.00, is
considered to be Treatment Level 1 (TL1) applied by gravity to a gravel -filled trench.
Delete C.
Table 30-10-2 — No change.
Amend Table 30-10-3
Size Adjustment Factors for Types of
Distribution Media in Soil Treatment Areas
Type of Soil Treatment Area
Trench or bed
Category 1
Rock or Tire Chips
1.0
Type of Storage/Distribution Media
Used in Soil Treatment Area
Category 2
Other Manufactured Media
0.9
Category 3
Chambers or
Enhanced
Manufactured
Media
0.7
. All proprietary distribution products must receive acceptance and the applicable reduction through
Colorado Water Quality Control Division review per the applicable requirements of Regulation 43
section 43.13.
Amend Sec. 30-10-40. Design of distribution systems.
A. General.
1. The infiltrative surface and distribution laterals must be level.
2. The infiltrative surface must be no deeper than four (4) feet below grade. The depth of the
infiltrative surface will be measured on the up -slope side of the trench or bed.
3. thru 6. — No change.
7. Backfilling and compaction of soil treatment areas must be accomplished in a manner that
does not impair the intended function and performance of the storage/distribution media
and soil and distribution laterals, allows for the establishment of vegetative cover,
minimizes settlement and maintains proper drainage.
8. Dosing may be used for soil treatment area distribution. The dose must be sized to account
for the daily flow and the dosing frequency.
B. Distribution Laterals; Must meet the requirements of Section 30-90-40, as applicable.
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1. Distribution between laterals in a soil treatment area must be as level as possible. Uneven
settling of portions of the distribution system following construction must be addressed by
provisions in the design to adjust flows between laterals.
2. The maximum length of distribution laterals must not exceed one hundred fifty (150) feet.
3. Distribution laterals longer than one hundred (100) feet must be pressure dosed or the
application of the effluent must be at the center of the lateral through a distribution box.
4. For absorption beds, the separating distance between parallel gravity distribution laterals
must not exceed six feet (center -to -center), and a distribution lateral must be located within
three feet of each sidewall and endwall.
5. The end of a distribution pipe must be capped unless it is in a bed or trenches in a level
soil treatment area, where the ends of the lines may be looped.
6. To promote equal distribution to the soil treatment area, the forcemain or effluent pipe
must be connected to as near to the middle of the distribution header as possible.
However, it must be offset from any distribution lateral to prevent preferential flow.
7. Orifices must be oriented downward unless pressure distribution is used and provision for
pipe drainage is included.
C. Pressure Distribution.
1. Design of pressure distribution systems must include:
a. Dose size and frequency for either proposed flows and soil type, or media long-term
acceptance rate;
b. Pipe diameter and strength requirements;
c. Orifice size and spacing;
d. A 30 — 72 inch operating head at the distal end orifice;
e. Pump/siphon information; Total Dynamic Head; gallons/minute;
f. Drain -back volume from forcemain; and
9.
Calculations, or a design software reference, that indicates the selected component
sizing will provide equal flow within each active zone of the distribution system, and
provide no more than a 10% flow differential from the initial orifice to the most distal
end orifice within each zone.
2. The separating distance between parallel distribution pipes in a pressure distribution
absorption bed must not exceed four feet, and the outer distribution pipe must be located
within two feet of each sidewall and endwall. Specific requirements for the design of sand
filters are noted in section 30-11-30.B.
3. Flushing assemblies must be installed at the distal end of each lateral and be accessible
from finished grade. A sweeping 90 degree or bends limited to 45 degree must be
provided.
Delete 5. Inspection ports.
Add and Amend Sec. 30-10-50. Soil Treatment Area Requirements
A. Trenches.
1. Trenches must be three (3) feet wide or less.
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2. The separating distance between trenches must be a minimum of four (4) feet, sidewall-
to-sidewall.
3. Distribution laterals used in a trench must be as close to the center of the trench as
possible.
B. Beds.
1. Maximum width for a bed shall be twelve (12) feet, unless the bed receives effluent
meeting Treatment Level 2 quality or better.
2. The separation distance between beds must be a minimum of six (6) feet, sidewall to
sidewall.
C. Serial and sequential distribution.
1. A serial or sequential distribution system may be used where the ground slope does not
allow for suitable installation of a single level soil treatment area, unless a distribution box
or dosing chamber is used.
2. The horizontal distance from the side of the absorption system to the surface of the
ground on a slope must be adequate to prevent lateral flow and surfacing.
3. Adjacent trenches or beds must be connected with a stepdown/relief line or a drop box
arrangement such that each trench fills with effluent to the top of the gravel or chamber
outlet before flowing to succeeding treatment areas.
D. Alternating systems.
1. An alternating system must have two (2) or more zones that must be alternated on an
annual or more frequent basis.
2. For repairs, each section must be a minimum of fifty percent (50%) of the total required
soil treatment area. For new installations, each separate soil treatment area must meet
the minimum sizing requirements of this regulation.
3. A diversion valve or other approved diversion mechanism that requires the owner or
operator to manually alternate zones of the OWTS may be installed on the septic tank
effluent line allowing soil treatment area sections to be alternated.
4. The diversion mechanism must be readily accessible from the finished grade.
E. Sequencing zone systems.
1. Sequencing zone systems have two (2) or more soil treatment area sections that are
dosed on a frequent rotating basis.
2. Where soil conditions are similar between the sections, each section area must be the
same size. If soil conditions are such that long-term acceptance rates are different, each
section may be sized for the same dose, but different long-term acceptance rates.
3. and 4. — No change.
F. Inspection Ports.
1. A 4 -inch inspection port accessible from ground surface must be installed at the terminal
end of each lateral in a trench system and at each corner of a bed system. The bottom
of the inspection port tube must extend to the infiltrative surface and not be connected to
the end of the distribution pipe.
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2. Inspection ports in chambers may be installed according to manufacturer's instructions if
the infiltrative surface is visible and effluent levels can be observed from the inspection
port.
3. Additional inspection ports connected to distribution pipes may be installed.
4. The top of the inspection ports may be terminated below the final grade if each is housed
in a component such as a valve box for a lawn irrigation system and has a removable
cover at the ground surface.
Amend Sec. 30-10-60. Storage/Distribution Media
A. Rock and Pipe.
1. The perforated pipe must be surrounded by clean, graded gravel, rock, or other material
of equal efficiency which may range in size from 1/2 inch to 2 1/2 inches. AASHTO M 43
size No. 3 coarse aggregate meets this specification.
2. At least six inches of gravel, rock or other material must be placed below the pipe. The
gravel, rock or other material must fill around the pipe and be at least two inches above
the top of the distribution pipe.
3. The top of the placed gravel or such material used must be covered with non -woven
permeable geotextile meeting a maximum thickness rating of 2.0 ounces per square yard
or equivalent pervious material. An impervious covering must not be used.
B. Chambers.
1. Chambers must be installed with the base of the unit on in -situ soil or, if placed on
acceptable media, the manufacturer's installation instructions must be followed so as to
prevent chambers from settling into the media.
2. Installation must be according to manufacturer's instructions.
3. Effluent may be distributed by gravity, pump or siphon.
4. If the width of a proprietary manufactured distribution product is within 90 percent of the
width of the excavation, it may be approved as being equivalent to the full width of the
excavation, if information is provided that demonstrates distribution of the full width. Thus,
the product must cover at least 90 percent of the excavated area in either a trench or bed
configuration in order to receive sizing adjustments provided in Table 30-10-3.
C. Media, Enhanced, or Other Manufactured
1. Manufactured media must be installed with the base on the in -situ soil or placed on
acceptable media meeting the manufacturer's specifications for proprietary distribution
products or combined treatment/distribution products.
2. Installation must be according to manufacturer's instructions.
3. Pressure distribution is required for TL2-TL3N effluent, unless otherwise noted in this
regulation.
D. Driplines.
1. The infiltrative surface area must be calculated using the long-term acceptance rate for
the site or a more conservative value if recommended by the manufacturer.
2. Driplines must be installed on manufacturer's spacing recommendations.
3. Drainback must be provided for all driplines, pipes and pumps.
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4. Provisions must be made to minimize freezing in the distribution pipes, driplines, relief
valves, and control systems.
5. Provisions must be made for filtering, back -flushing, or other cleaning.
E. Tire Chips.
1. The pipe may be surrounded with clean, uniformly -sized tire chips.
2. Tire chips must be nominally two inches in size and may range from 1/2 inch to a maximum
of four inches in any one direction.
3. Wire strands must not protrude from the tire chips more than 0.75 inches.
4. Tire chips must be free from balls of wire and fine particles less than two mm across.
5. The top of the tire chips used must be covered with non -woven permeable geotextile
meeting a maximum thickness rating of 2.0 ounces per square yard or equivalent pervious
material. An impervious covering must not be used.
Amend Sec. 30-10-70. Lift stations.
Lift stations intended solely for the purpose of delivering sewage to a septic tank, or septic
tank effluent to a standard soil treatment area that is located such that it is not possible to provide
gravity flow from the septic tank to the soil treatment area, are not required to be designed by a
professional engineer. The systems installer shall submit to the Division a pump information form,
provided by the Division, for documentation.
Amend Sec. 30-10-80. Soil replacement.
A. The construction of a soil replacement system is permitted to bring the soil treatment area
into compliance with the requirements of this regulation.
1. When a soil type "R" is removed, the following requirements must be met:
a. All added soil must comply with the following specifications:
1) Added soil must meet the specifications of either "preferred" or "secondary" sand
filter media, as specified in section 30-11-30 B.4.
2) The long-term applicable rates as specified in Table 30-10-1A must be used. No
additional sizing adjustments are allowed.
3) The depth of the added media must comply with the requirements of Table 30-10-
1A.
4) A gradation of the sand media used must be provided. The gradation must be
dated no more than one month prior to the installation date. However, a gradation
of the actual material placed in the excavation is recommended.
5) All added soil must be completely settled prior to installation of components as
specified and approved by the design engineer.
6) Pressure distribution must be used.
2. The removal and reinstallation of in -situ soil may only be allowed where the soils are
determined to be a soil type "R-1" (Option 2). The design must comply with the
requirements for this soil type noted in Table 30-10-1A (Soil Type R-1, Option 2).
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3. When a sand media is added to soil treatment area or to an excavation where a soil type
1-5 (Table 30-10-1) is the underlying soil, the following requirements must be met:
a. Added soil must meet the specifications of either "preferred" or "secondary" sand filter
media, as specified in section 30-11-30 B.4.
b. Unless the design follows the criteria for a sand filter or mound system design as
required in section 30-11-30, the TL1 long-term acceptance rate for the receiving soil
must be used.
c. A gradation of the sand media used must be provided. The gradation must be dated
no more than one month prior to the installation date. However, a gradation of the
actual material placed in the excavation is recommended.
d. All added soil must be completely settled prior to installation of components.
Amend Sec. 30-10-90. Repairs.
A. When space is not available or if there are other site limitations that preclude other soil
treatment area options for OWTS repairs, wide beds, deep beds and deep gravel trenches
may be considered for repairs only. Other options are vaults (in accordance with Section 30-
12-40 of this Chapter) or higher level treatment systems.
B. Repairs to failing systems must conform to setbacks identified in Table 30-7-1 when possible.
When this is not possible using all available methods described above, the jurisdiction with
authority may permit reductions to setbacks. At no point will a setback reduction be approved
by the jurisdiction less than what the existing separation is to existing OWTS. In maximizing
this setback distance, all methods available in section 30-10-90 A. must be utilized including
but not limited to the use of Higher Level Treatment, wide beds, etc., where allowed. Any
setback reduction beyond what the existing failing system presents must be approved by the
local board of health as outlined in section 30-4-140.
C. Wide beds. For repairs, beds may be wider than twelve (12) feet without being required to
receive effluent meeting Treatment Level 2 quality or better.
D. Deep Beds: For repairs, the infiltrative surface of a bed may be no deeper than five feet. Size
adjustments as provided for in Tables 30-10-2 and 30-10-3 must not be applied. System sizing
will be based strictly on the soil type and corresponding LTAR.
E. Deep gravel trenches.
1. The length of an absorption trench may be calculated by allowance for the sidewall area
of additional depth of gravel in excess of six (6) inches below the bottom of the
distribution pipe, according to the following formula:
Adjusted length = L x (W+2)
(W+1+2D)
Where:
L = Length of trench prior to adjustment for deep gravel
W = Width of trench in feet
D = Additional depth in feet of gravel in excess of the minimum required 6 inches of
gravel below the distribution pipe
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2. Maximum allowable additional depth is five (5) feet.
3. Percolation tests or soil profile test pit excavations must be performed at the proposed
infiltrative surface depth.
4. Size adjustments as provided for in Table 30-10-2 and 30-10-3 must not be applied to
deep gravel trenches.
F. Wastewater Ponds.
1. Construction of new wastewater ponds is prohibited.
2. For repairs of an existing wastewater pond, the potential for risk to public health and water
quality may be evaluated by the local public health agency. If risk is low in the
determination of the local public health agency, the repair of a wastewater pond may be
permitted, however the following criteria must be followed:
a. A septic tank must precede the wastewater pond.
b. The depth of the design volume of the wastewater pond must be at least five feet.
c. A wastewater pond must have two feet of free board above the design volume of the
pond.
d. A wastewater pond must be fenced to keep out livestock, pets, vermin, and
unauthorized people.
e. Wastewater ponds must be designed on the basis of monthly water balance including
design flow, precipitation, evaporation, and seepage.
f. Wastewater ponds must be constructed so the seepage out of the bottom or sides
does not exceed 1/32 of an inch per day. If this limit cannot be achieved using
compacted natural soil materials including soil additives, an impermeable synthetic
membrane liner must be used.
g. If the evapotranspiration does not exceed the rate of inflow of effluent from the
structure, a soil treatment area meeting the requirements of this regulation must be
installed to accept the excess flow.
h. Maintenance must include preventing aquatic and wetland plants from growing in or
on the edge of the pond, protecting sides from erosion, and mowing grasses on the
berm and around the pond.
i. Wastewater ponds must be designed by a professional engineer.
G. Vaults. The allowable use of vaults for repairs must meet the criteria specified in Section 30-
12-20 of this Chapter.
H. Higher level treatment options.
1. Design criteria for higher level treatment systems are in Article XI below.
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ARTICLE XI - Design Criteria - Higher Level Treatment Systems
Amend Sec. 30-11-20. Treatment levels.
The treatment levels identified in Table 30-6-3 are specified in this Section for public domain
technology, and proprietary systems will be assigned to a treatment level approved by the Water
Quality Control Division. Adequate maintenance and operation plan as required by the Water
Quality Control Division must be submitted to the Division.
Amend Sec. 30-11-30. Sand filters.
A. A lined or unlined intermittent sand filter or recirculating sand filter, may be used as a higher
level -treatment system prior to dispersing the effluent into a soil treatment area.
B. Intermittent (single -pass) sand filters; General Requirements.
1. The treatment level for intermittent sand filters is considered TL3.
2. General Design Parameters: Not all combinations of the variables noted below will result
in a proper distribution system design. The design engineer must justify through
calculations or design software that the selected values will concur with industry
standards.
a. Distribution pipe size: 3/4 inch — 1.5 inches (PVC Class 200, min.)
(1) 2 inch distribution pipe may only be used where other design modifications cannot
overcome a greater than 10% variation in the pressure head between the initial
and distal orifices.
(2) Distribution pipe spacing: 18 inches — 48 inches
(3) Orifice size: 1/8 inches — 3/8 inches (Also see section 30-11-30 E.1. below)
(4) Orifice spacing: 18 inches — 48 inches
(5) Operating head at the distal end of distribution pipes: 30 inches — 72 inches (60
inches typ.). Larger orifices allow for an operating head at the lower end of this
range, while smaller orifices will necessitate an operating head at the higher end
of this range.
3. Dosing:
a. Pressure distribution is required. The design of the distribution system must also
comply with the requirements of 30-10-40 C.1.
b. Number of cycles/day: Will vary with design (Short, frequent doses are preferred.)
c. Proposed dose volume: Will vary with design (0.25 - 1.0) gallons/orifice/dose, or 3-5
times distribution pipe volume
d. Timed dosing is recommended where design considerations allow.
4. Sand Filter Treatment Media
a. The depth of the sand media below the distribution system must be at least 24 inches
unless otherwise noted in Table 30-10-1A for type "R" soils.
b. "Preferred" sand media requirements:
(1) Effective size: 0.25-0.60 mm
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(2) Uniformity coefficient: ≤ 4.0
(3) Percent fines passing #200 sieve: ≤ 3.0
c. "Secondary" sand media requirements:
(1) Effective size: 0.15-0.60 mm
(2) Uniformity coefficient: ≤7.0
(3) Percent fines passing #200 sieve: ≤ 3.0
d. A gradation of the sand media used must be provided. The gradation must be dated
no more than one month prior to the installation date. However, a gradation of the
actual material placed in the excavation is recommended.
5. Gravel Requirements
a. Clean, graded gravel, or rock, must range in size from 1/2 inch to 2 1/2 inches.
AASHTO M 43 size No.3 coarse aggregate meets this specification.
(1) The gravel must surround the distribution pipes used to disperse the effluent and
must be at least 6 inches below and 2 inches above the pipes.
(2) Water Quality Control Division accepted manufactured media may be used as an
alternative to specified gravel.
6. Filter Fabric Requirements
a. The top layer of gravel must be covered with a non -woven permeable geotextile fabric
meeting a maximum thickness rating of 2.0 ounces per square yard or equivalent
pervious material.
7. Final Cover Material
a. 8 inches — 10 inches of Type 1 or 2 soil with an additional 2 inches top soil
8. Size adjustment factors provided in Tables 30-10-2 and 30-10-3 are not applicable for
sand filters.
9. Sand filters must not be used to treat wastewater that does not conform to TL1 treatment
level or better.
C. Unlined (open bottom) sand filters.
1. All requirements for 30-11-30 B. 1-9 will apply to unlined sand filters.
2. Application rates:
a. Maximum hydraulic loading rate for TL1 effluent applied to "Preferred Sand Media" in
an unlined sand filter is 1.0 gal./sq.ft./day, or the long-term acceptance rate of the
receiving soil for TL1 (Table 10-1) whichever results in the larger area.
b. Maximum hydraulic loading rate for TL1 effluent applied to "Secondary Sand Media"
in an unlined sand filter is 0.8 gal./sq.ft./day, or the long-term acceptance rate of the
receiving soil for TL1 (Table 10-1) whichever results in the larger area.
c. Maximum hydraulic loading rate for TL2, TL2N, TL3, or TL3N effluent applied to
"Preferred" or "Secondary" Sand Media in an unlined sand filter must be the long-
term acceptance rate of the receiving soil for TL1, (Table 10-1).
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3. The upper infiltrative surface of an unlined sand filter receiving TL1 — TL3N effluent must
be at least three (3) feet above a limiting layer.
D. Lined Sand Filters
1. All requirements of 30-11-30 B.1-9 will apply to unlined sand filters.
2. Application rates:
a. Hydraulic loading rate for TL1 effluent applied to "Preferred Sand Media" in a lined
sand filter is 1.0 gal./sq.ft./day.
b. Hydraulic loading rate for TL1 effluent applied to "Secondary Sand Media" in a lined
sand filter is 0.8 gal./sq.ft./day.
3. The minimum depth of the sand media in a lined sand filter must be two feet.
4. An intermediate layer of pea gravel, two inches in thickness, must be placed between the
sand filter media and the coarse under -drain media to prevent the migration of sand into
the lower layer of under -drain gravel. ASTM C 33, No. 8, coarse aggregate meets this
specification.
5. A minimum four -inch diameter slotted SCH40 PVC under -drain pipe must be used to
collect the treated effluent. The under -drain pipe must be installed in the center of a 5
inches thick bed of washed, graded gravel, or rock ranging in size from 1/2 inch to 2 1/2
inches. AASHTO M 43, No.3 coarse aggregate meets this specification. Lined sand filters
must have an impervious liner on the sides and bottom of the filter. The liner must consist
of a minimum 30 mil thick PVC material or equivalent.
6. Effluent collected by the under -drain must be dispersed to a soil treatment area. The soil
treatment area may be sized with a maximum long-term acceptance rate of the receiving
soil for TL1 effluent.
E. Recirculating Sand Filter, Minimum Requirements:
1. Treatment level:
a. Treatment level provided within recirculating sand filters is TL3.
1) General Design Parameters: Not all combinations of the variables noted below will
result in a proper distribution system design. Engineer must justify through
calculations or design software that the selected values will concur with industry
standards.
b. Distribution pipe size: 3/4 inch — 2 inches (PVC Class 200, min.)
c. Distribution pipe spacing: 18 inches — 36 inches (24 inches typ.)
d. Orifice size: 1/8 inch — 1/4 inch
e. Orifice spacing: 18 inches — 36 inches (24 inches typ.)
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f. Pressure head at end of distribution pipe: 24 inches — 72 inches (60 inches typ.)
2. Dosing:
a. Timed dosed, pressure distribution is required. The design of the distribution system
must comply with the requirements of section 30-10-40 C.1.
b. Recirculation ratio: 3:1 — 5:1
c. Gallons/orifice/dose: 1 — 3 (2.0 typ.)
d. Hydraulic loading: 3 - 5 gal./sq.ft./day (4 — 5 typ.)
e. Dosing time "ON"; <2.5 min. (<2.0 typ.)
f. Number of cycles/day: 48 — 120
3. Top gravel requirements:
a. Washed, graded gravel, or rock, must range in size from 1/2 inch to 2 1/2 inches.
AASHTO M 43, No.3 coarse aggregate meets this specification.
b. The gravel must surround the distribution pipes used to disperse the effluent and must
be at least 6 inches below and 2 inches above the pipes.
c. State accepted manufactured media may be used as an alternative to specified gravel.
d. Soil cover is prohibited. The upper gravel layer must be open to the atmosphere.
4. Filter media requirements:
a. Effective size: 1.5 — 2.5 mm
b. Uniformity coefficient: ≤ 3
c. Fines passing #200 sieve: ≤ 1.0
d. Media depth (min.): ≥24 inches
5. Intermediate gravel layer:
a. An intermediate layer of pea gravel, two inches in thickness, must be placed between
the coarse under -drain media and the sand filter media to prevent the migration of
sand into the lower layer of under -drain gravel (ASTM C 33, No. 8, coarse aggregate).
6. Under -drain requirements:
a. A minimum four -inch diameter slotted SCH40 PVC under -drain pipe must be used to
collect the treated effluent. The under -drain pipe must be installed in the center of a 5
inches thick bed of washed, graded gravel, or rock ranging in size from 1/2 inch to 2
1/2 inches. AASHTO M 43, No.3 coarse aggregate meets this specification.
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7. PVC liner requirements:
a. Lined sand filters must have an impervious liner on the sides and bottom of the filter.
The liner must consist of a 30 mil thickness PVC material or equivalent.
b. Effluent collected from the recirculating sand filter must be discharged to a soil
treatment area. The soil treatment area may be sized with a maximum long-term
acceptance rate of the receiving soil for TL1 effluent.
Add Sec. 30-11-40. Mound Systems.
A. When the infiltrative surface area of the media receiving wastewater effluent is at or above
the natural ground surface at any point, it shall be considered a mound system.
B. Mound systems that provide a minimum of 24 inches of sand treatment media may use the
application rates for the in -situ receiving soil for TL1 effluent (Table 10-1). Size adjustment
factors within Table 30-10-3 may be applied if TL1 application rates are used.
C. Mound systems must conform to the design requirements of sections 30-11-30 C.1-5 for
unlined (open bottom) sand filters, with the following exceptions.
1. A mound system may include less than 24 inches of imported sand media on a site where
a lesser depth of sand media is sufficient to meet vertical separation requirements above
a limiting layer. Application rates for the in -situ receiving soil for TL1 effluent must be used
when less than 24 inches of sand media is used, unless higher level treatment is provided
prior to dispersal into the mound system.
2. For the design of a mound system where less than 24 inches of sand media is proposed,
and application rates for TL1 are used, the size adjustment factors within Table 30-10-3
may be used.
D. The basal area must be determined using the LTAR from Table 30-10-1 for the in -situ
receiving soil under the mound.
E. Linear loading rates must be determined. The evaluation of many factors is required for an
accurate determination of the linear loading rate. While application rates for the in -situ
receiving soil under the mound is a main component, placement on the slope, and percent of
the slope must also be addressed when defining the linear loading rate. If the movement of
the effluent is primarily vertical, then the linear loading rate is not as critical. However, if the
movement of the effluent will be primarily horizontal, as would be expected in soil types 3A
through 5 (Table 30-10-1), then the linear loading rate is extremely important and long narrow
mounds are strongly recommended.
1. When TL1 effluent is applied to the distribution media of a mound system installed above
in -situ soil types 1 through 3 (Table 30-10-1) and R-0 through R-2 (Table 30-10-1A), the
suggested linear loading rate is between 6 gpd/lin.ft. and 12 gpd/lin.ft. The maximum width
of the distribution media in a mound system installed above these soil types is 12 feet
when TL1 effluent is applied to the distribution media of a mound system.
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2. When TL2 through 3N effluent is applied to the distribution media of a mound system
installed above in -situ soil types 1 through 3 (Table 30-10-1) and R-0 through R-2 (Table
30-10-1A), the linear loading rate may exceed 12 gpd/lin.ft.; subsequently the mound may
be wider than 12 feet.
3. When TL1 through TL3N effluent is applied to mound systems installed above in -situ soil
types 3A through 5 (Table 30-10-1), the suggested linear loading rate is between 3
gpd/lin.ft. and 5 gpd/lin.ft. The maximum width of the distribution media in a mound system
placed above these soil types is 12 feet.
F. The final cover over a mound system must extend at least twelve inches horizontally beyond
the perimeter of the distribution media prior to sloping down to existing grade. The final slope
of the mound must be no greater than three feet horizontal to one foot vertical.
G. The surface of the mounded area must be planted with a suitable vegetative cover.
H. A suggested reference for the design and installation of mound systems is, "The Wisconsin
Mound Soil Absorption System: Siting, Design, and Construction Manual, January 2000".
Note that this is suggested guidance, and where the requirements of this regulation differ from
those in the referenced mound document, the requirements of this regulation will govern in
those cases.
Amend Sec. 30-11-50. - Rock plant filter (constructed wetland) treatment before soil
treatment area.
Remainder of Section — No change.
ARTICLE XII - Design Criteria - Other Facilities
Amend Sec. 30-12-10. - Evapotranspiration and evapotranspiration/absorption systems.
A. Non -Pressurized Drip Dispersal System (NDDS):
1. An NDDS is considered a type of evapotranspiration/absorption system. However as
specific design criteria is provided for an NDDS, they are exempt from the additional
requirements of section 30-12-10 B, C and D.
2. The Colorado Professionals in Onsite Wastewater Guidelines for the Design and
Installation of Non -Pressurized Drip Dispersal Systems (NDDS), September, 2016 is the
procedural guideline in the design of a NDDS and must be followed when an NDDS is
proposed.
3. The width of an NDDS system may be wider than 12 feet.
B. The following section provides general criteria which must be followed when an
evapotranspiration or evapotranspiration/absorption bed is proposed.
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1. The design may only be permitted in arid climates where the annual evaporation rate
exceeds the annual precipitation rate by more than 20 percent, and where site
characteristics dictate that conventional methods of effluent dispersal are not appropriate.
2. The design may only bepermitted in soil types 4, 4A and 5 .
3. The system must be designed by a professional engineer.
4. If data for the Pan Evaporation Rate is provided, it must be multiplied by 0.70, or less, to
obtain the equivalent Lake Evaporation Rate.
5. The width of the bed may be wider than 12 feet.
6. The required capillary or wicking sand must meet the gradation requirements in Table 12-
1 and be approved by the design engineer. This sand is to be covered by a crowned, thin
layer of loamy -sand mix and appropriate vegetation that will assist in drawing the water to
the surface.
7. Adjustment factors as provided in Tables 30-10-2 and 30-10-3 must not be used.
Add Table 30-12-1 Gradation of Wicking Sand for Evapotranspiration Beds (Fine Sand)
Sieve Size
Percent Passing
4
100
40
50-70
200
<15
C. For systems designed strictly as an evapotranspiration bed, the following criteria must be met:
1. Design data to be furnished must include, but shall not be limited to: system dimensions,
distribution system design; specifications of distribution media and wicking sand, liner
material if used, bedding; properties of the soil under the system, vegetative cover, and
a water balance calculation including annual precipitation and storage requirements for
periods of the year when evapotranspiration does not occur.
2. The following formula must be used for determining the minimum area necessary for
total evapotranspiration of septic tank effluent:
Area (in square feet)* = Design flow (in gallons per day) x 586
Lake evaporation rate at the site (in inches per year)
* Additional area may be required based on the annual water balance calculations.
3. Designs will include a rock and pipe, or other Water Quality Control Division approved
proprietary distribution product, with the centerline of the distribution system 6 to 8 feet on
center. A thin non -woven fabric may be placed above the distribution system. Capillary
wicking of the effluent is accomplished by a uniform depth layer of the specified sand
media (capillary wicks), no more than 24 inches deep, placed between and above the
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distribution media. The base of the evapotranspiration bed may be no more than 30 inches
below finished grade.
4. Capillary wicks which penetrate between the distribution system to the bottom of the bed,
must be at least 15 percent of the bed surface area. The wicks must be uniformly spaced
throughout the system.
5. Except for dwellings, ft the system is designed for summer use only, the surface area
may be multiplied by 0.6 to obtain the required area.
D. For systems designed as an evapotranspiration/absorption bed, the following criteria must be
met.
1. Data to be furnished must include, but is not limited to: system dimensions, distribution
system design, specifications of wicking sand, properties of the soil under the
evapotranspiration/absorption bed, provision for vegetation cover, and a water balance
calculation including annual precipitation and storage requirements for periods of the year
when evapotranspiration does not occur.
2. Design will include a rock and pipe, or other Water Quality Control Division approved
proprietary distribution product, with the centerline of the distribution system 6 to 8 feet on
center. A thin non -woven fabric may be placed above the distribution media. Capillary
wicking of the effluent is accomplished by a uniform depth layer of the specified sand
media (capillary wicks) no more than 24 inches deep placed between and above the
distribution media. The infiltrative surface may be no more than 30 inches below finished
grade.
3. Capillary wicks which penetrate between the distribution system to the bottom of the bed,
must be at least 15 percent of the bed surface area. The wicks must be uniformly spaced
throughout the bed.
4. Amount of storage and evapotranspiration capacities may be reduced by the volume of
effluent absorbed by the underlying soil based on the long-term acceptance rate for that
soil type and the formulas provided in section 30-12-10 D.5. below.
5. The following formula must be used for determining the minimum area necessary for
evapotranspiration/absorption of septic tank effluent:
(1) Area (sq. ft.)* = Flow (qpd)
(LTAR + ETR)
a. LTAR refers to the long-term acceptance rate of the underlying soil as provided in
Table 30-10-1 for TL1 effluent.
b. ETR refers to the evapotranspiration rate derived from the following formula:
ETR (gal./day sq. ft.) = Lake Evaporation Rate at the Site (in inches per year)
586
* Additional area may be required based on the annual water balance calculations.
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Amend Sec. 30-12-20. Vaults other than vault privies.
A. and B. — No change.
C. A vault must have a minimum five -hundred -gallon effective volume or be capable of holding
a minimum of the 48 hour design wastewater flow, whichever is larger.
D. thru F. — No change.
Amend Sec. 30-12-30. Vault privies.
A. Effective volume of the vault privy must be no less than four hundred (400) gallons, and it
must be constructed of concrete or plastic. The vaults for privies must meet the structural and
watertightness standards of vaults.
B. A vault privy must be built to include: fly- and rodent -tight construction, a superstructure
affording complete privacy, an earth mound around the top of the vault and below floor level
that slopes downward away from the superstructure base, a floor and a riser of concrete or
other impervious materials with hinged seats and covers of easily cleanable, impervious
material. All venting must be fly -proofed with No. 16 or tighter mesh screening.
C. A signal device is not required for a vault privy.
D. A permit fee, as set by the Board of County Commissioners, shall be required of applicants
for any system that requires only a vault or holding tank. An application for an OWTS permit
must be completed by the owner and a final inspection must be made by the Division with
proper notice as specified in Section 30-4-70 of this Chapter.
Amend Sec. 30-12-40. Incinerating, composting and chemical toilets.
A. The use of an incinerating, composting or chemical toilet will not reduce the required size of
the OWTS as noted in Section 30-8-10.
B. Incinerating and composting toilets may be permitted. Incinerating and composting toilets
shall bear the seal of approval of the NSF or an equivalent test and certification program.
C. Permitting of an incinerating or composting toilet may also be subject to the jurisdiction of a
local agency regulating plumbing or the Colorado Plumbing Board, whichever has jurisdiction
over plumbing in the location.
D. An incinerating or composting toilet may be used for toilet waste where an OWTS is installed
for treating wastewater remaining after removal of toilet waste. Subject to Board of Public
Health or other applicable regulations or codes (e.g., Colorado Plumbing Code if a local code
does not exist), the compartment may be located within a dwelling or building, provided that
the unit complies with the applicable requirements of this Regulation and provided that the
installation will not result in conditions considered to be a health hazard as determined by the
Division. Compartment and appurtenances related to the unit must include fly -tight and
vector -proof construction and exterior ventilation.
E. Incinerating toilets. An approved incinerating toilet must be designed and installed in
accordance with all applicable federal, state and local air pollution requirements and
manufacturer's instructions.
1. Incinerating Toilets Acceptance Requirements
a. Incinerating toilets must meet the requirements of the NSF Protocol P157 and bear
the seal of approval of the NSF or an equivalent testing and certification program.
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b. Incinerating toilets must be operated according to manufacturer's specifications.
F. Composting toilets.
1. Composting toilets must meet the requirements of NSF/ANSI Standard 41 and bear the
seal of approval of the NSF or an equivalent testing and certification program.
2. An approved composting toilet must treat deposits of feces, urine and readily
decomposable household garbage that are not diluted with water or other fluids and are
retained in a compartment in which aerobic composting will occur.
3. The effective volume of the receptacle must be sufficient to accommodate the number
of persons served in the design of the unit installed. The effective volume of the unit must
include sufficient area for the use of composting materials, which must not be toxic to
the process or hazardous to persons and which must be used in sufficient quantity to
assure proper decomposition.
4. Residue from the composting toilet must be removed when it is filled to seventy-five
percent (75%) of capacity. Residue from the unit must be properly disposed of by
methods recommended by the manufacturer and acceptable to the Division. Disposal
methods must prevent contamination of water and not cause a public health nuisance.
Disposal using solid waste practices is recommended.
5. If a system will be installed where low temperature may be a factor, design and
installation must address the effects of the low temperature.
6. Composting toilets must be operated according to manufacturer's specifications.
G. Portable chemical toilets.
1. A portable chemical toilet may be used by permit from the Division.
2. Use of a portable chemical toilet in permanently occupied buildings is prohibited except
during construction or under emergency circumstances as determined by the Division.
Proper ventilation of a chemical toilet used inside must be required.
Amend Sec. 30-12-50. Treatment systems other than those discharging through a soil
treatment area or sand filter system.
A. — No change.
B. Systems that discharge other than through a soil treatment area or a sand filter system must:
1. Be designed by a professional engineer;
2. Be reviewed by the Board of Public Health; and
3. Not pose a potential health hazard or private or public nuisance or undue risk of
contamination.
4. Not allow drainage of effluent off of the property of origin.
C. — No change.
D. The following minimum performance criteria must be required for all permitted systems
pursuant to this Section:
1. If effluent discharge is made into areas in which the possibility exists for occasional direct
human contact with the effluent discharge, the effluent at the point of discharge must
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meet the minimum treatment criteria of TL3 effluent and specifically adhere to each of
the following standards:
a. The geometric mean of the E. coli density must not exceed fifteen (15) per one
hundred (100) milliliters when averaged over any five (5) consecutive samples, and
no single sample result for E. coli can exceed one hundred twenty-six (126) per one
hundred (100) milliliters.
b. and c. — No change.
2. If the effluent discharge is made into an area so restricted as to protect against the
likelihood of direct human contact with the discharged effluent, the effluent, at the point
of discharge, must meet the treatment criteria of TL2 effluent and specifically adhere to
each of the following standards:
a. The geometric mean of the E. coli density must not exceed one hundred twenty-six
(126) per one hundred (100) milliliters when averaged over any five (5) consecutive
samples and no single sample can exceed three hundred twenty-five (325) E. coli
per one hundred (100) milliliters.
b. and c. — No change.
E. To determine compliance with the standards contained in this Section, the required sampling
frequency for E. coli, CBOD 5 and total suspended solids levels must be performed at least
once per month when the system is in operation and the results submitted to the Division for
compliance with the permit requirements.
F. — No change.
ARTICLE XIII — OPERATION AND MAINTENANCE
Amend Sec. 30-13-30. Monitoring and sampling.
A. For an OWTS for which monitoring of effluent is required, a delegated third party must collect
and test effluent samples to ensure compliance with the provisions of this Regulation.
B. Sampling may be required by the Division in conjunction with an enforcement action.
C. Any owner or occupant of property on which an OWTS is located may request the Division
to collect and test an effluent sample from the system. The Division may perform such
collection and testing services. The owner or occupant must pay for these services.
1. If the Division or a delegated third party collects and tests effluent samples, a fee not to
exceed that which is allowed by the OWTS Act may be charged for each sample
collected and tested. Payment of such charge must be stated in the permit as a condition
for its continued use.
2. Conditions when the Division can require routine monitoring, including but not limited to:
a. Indications of inadequate performance;
b. Location in sensitive areas; and
c. Experimental systems.
D. Sampling and analysis must be performed according to American Public Health Association,
American Water Works Association and Water Environment Federation: Standards Methods
for the Examination of Water and Wastewater , 21 St edition.
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Add ARTICLE XIV — TECHNOLOGY REVIEW AND ACCEPTANCE
Sec. 30-14-10. Technology Review and Acceptance
A. OWTS technologies must either be public domain, including, but not limited to, rock and pipe
distribution systems, sand filters with pressure distribution and mound systems, with criteria
for design, installation, maintenance and use as described in this regulation, or proprietary
products that have received Water Quality Control Division review and acceptance before the
Division may permit them for use, as stated in Section 43.13 of Regulation 43.
B. The Water Quality Control Division must review and provide either comment or acceptance to
the manufacturer for proprietary products in these technology categories:
1. Proprietary treatment products (e.g. treatment systems);
2. Propriety distribution products (e.g. manufactured distribution products or subsurface
dripline);
3. Septic tanks;
4. Others as needed.
Add ARTICLE XV — MATERIALS INCORPORATED BY REFERENCE
Sec. 30-15-10 Materials Incorporated by Reference
Throughout these regulations, standards and requirements by outside organizations have
been adopted and incorporated by reference. The materials incorporated by reference cited
herein include only those versions that were in effect as of April 10, 2017, and not later
amendments to the incorporated material.
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VIII PAM IIMIA IA & I/NM WU, BM
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Amend APPENDIX 30-B
SOIL CLASSIFICATION SYSTEM (SOIL -SEPARATE SIZE LIMITS)
SOURCE: USDA NRCS Field Book (pages 2-45)
USDA
Clay
fine I co.fine
FINE EARTH
Silt Sand
co. v.6. fi med. co co
fine
ROCK FRAGMENTS 6-
so
channers flags!
_ Gravel Cob -
_ tiles
medium '. coarse
15" 24•1
Sao 600 mm
stones boulders
Stones Boulders
millimeters: 0.0002
.002 mm
.02
.05 .1 .25 .5 1
2 mm
5 20 76 250 mm 600 mm
U.S. Standard Sieve No. (opening)
300 140 60 35 18
10
4 (3/4) (3) (10) (25)
International
Clay
Silt
Sand
fine coarse
Gravel
Stones
millimeters:
.002 mm
.02
.20
2 mm
20 mm
U.S. Standard Sieve No. (opening):
10
(3/4)
Unified
Silt or Clay
Sand
Gravel
Cobbles Boulders
fine medium
co.
fine coarse
millimeters:
.074 .42
2 mm
4.8 19 76 300 mm
U.S. Standard Sieve No. (opening):
200 40
10
4 (3/4) (3)
AASHTO
Clay
Silt
Sand
fine coarse
Gravel or Stones
fine med co.
Broken Rock (angular),
or Boulders (rounded)
millimeters:
.005 mm
.074 .42
2 mm
9.5 25 75 mm
U.S. Standard Sieve No. (opening).
200 40
10
(3/8) (1) (3)
phi#: 12 10
9 8 7
6
5
4 3 2 1 0
-1
-2 -3 4 .0 -6 -7 -8 -9 -10 -12
Modified
Wentworth
�l —clay
►1
—.4°°bb/, 4 boulders -1-►
►,4
silt
►� sand
pebbles
millimeters: .00025
.002 .004 .008
.016
.031
.062 .125 .25 .5 1
2
4 8 16 32 64 128 256 4092 mm
U.S. Standard Sieve No.:
230 120 60 35 18
10
5
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Carly Koppes, Clerk and Recorder, Weld County, CO
X111 N�rjp c N�irR� '�h�141 4�ht I�M;��' r�'�4tW1� W�h 1I III 64
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BE IT FURTHER ORDAINED by the Board that the Clerk to the Board be, and hereby is,
directed to arrange for Municode to supplement the Weld County Code with the amendments
contained herein, to coincide with chapters, articles, divisions, sections, and subsections as they
currently exist within said Code; and to resolve any inconsistencies regarding capitalization,
grammar, and numbering or placement of chapters, articles, divisions, sections, and subsections
in said Code.
BE IT FURTHER ORDAINED by the Board, if any section, subsection, paragraph,
sentence, clause, or phrase of this Ordinance is for any reason held or decided to be
unconstitutional, such decision shall not affect the validity of the remaining portions hereof. The
Board of County Commissioners hereby declares that it would have enacted this Ordinance in
each and every section, subsection, paragraph, sentence, clause, and phrase thereof irrespective
of the fact that any one or more sections, subsections, paragraphs, sentences, clauses, or
phrases might be declared to be unconstitutional or invalid.
The above and foregoing Ordinance Number 2017-10 was, on motion duly made and
seconded, adopted by the following vote on the 29th day of January, A.D., 2018.
ATTEST:
Weld C. my Clerk to the Boar
BY:
Deputy
the Bo
APPROVED ASrT = F=ORM:
Date of signature:
,,,County Attorney
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Carly Koppes, Clerk and Recorder, Weld County, CO
BOARD OF COUNTY COMMISSIONERS
WELD COUNTY, COLORADO
Stave Moreno, Chair
ie
Coza
"rit4,XL62..,„
Mike Freeman
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11111 MI:41''0 P40' M III
Publication: November 8, 2017
First Reading: December 18, 2017
Publication: December 27, 2017, in the Greeley Tribune
Second Reading: January 8, 2018
Publication: January 17, 2018, in the Greeley Tribune
Final Reading: January 29, 2018
Publication: February 7, 2018, in the Greeley Tribune
Effective: February 12, 2018
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Carly Koppes, Clerk and Recorder, Weld County, CO
•111 kirdinKI M Iifi11li�FN�flIIll UtriliNyk BIM
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WELD COUNTY
CODE ORDINANCE 2017-10
/&o 02 -9 -if
IN THE MATTER OF REPEALING AND REENACTING, WITH AMENDMENTS, CHAPTER 30
WELD COUNTY DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT ON -SITE
WASTEWATER TREATMENT SYSTEM REGULATIONS, OF THE WELD COUNTY CODE
BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF THE COUNTY OF
WELD, STATE OF COLORADO:
WHEREAS, the Board of County Commissioners of the County of Weld, State of
Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with
the authority of administering the affairs of Weld County, Colorado, and
WHEREAS, the Board of County Commissioners, on December 28, 2000, adopted Weld
County Code Ordinance 2000-1, enacting a comprehensive Code for the County of Weld,
including the codification of all previously adopted ordinances of a general and permanent nature
enacted on or before said date of adoption, and
WHEREAS, the Weld County Code is in need of revision and clarification with regard to
procedures, terms, and requirements therein.
NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
County of Weld, State of Colorado, that certain existing Chapters of the Weld County Code be,
and hereby are, repealed and re-enacted, with amendments, and the various Chapters are
revised to read as follows.
CHAPTER 30
WELD COUNTY DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT
ON -SITE WASTEWATER TREATMENT SYSTEM REGULATIONS
TABLE OF CONTENTS
ARTICLE I Authority
Sec. 30-1-10. Title.
Sec. 30-1-20. Jurisdiction, severability, savings clause.
Sec. 30-1-30. Effective date.
ARTICLE II Scope and Purpose
Sec. 30-2-10. Declaration.
Sec. 30-2-20. Purpose.
Sec. 30-2-30. Effluent discharged to surface waters.
ARTICLE III Definitions
Sec. 30-3-10. Definitions.
Sec. 30-3-20. Abbreviations and acronyms.
Table 30-3-1 Abbreviations and Acronyms
ARTICLE IV Administration and Enforcement
Sec. 30-4-10. General sanitation requirements.
Sec. 30-4-20. Existing OWTS review.
Sec. 30-4-30. Permit application requirements and procedures.
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1
Sec. 30-4-40.
Sec. 30-4-50.
Sec. 30-4-60.
Sec. 30-4-70.
Sec. 30-4-80.
Sec. 30-4-90.
Sec. 30-4-100.
Sec. 30-4-110.
Sec. 30-4-120.
Sec. 30-4-130.
Sec. 30-4-140.
Sec. 30-4-150.
Sec. 30-4-160.
Sec. 30-4-170.
Determination of compliance of permit submission.
Denial of permit application.
Access to site.
Notification and inspection stages.
Final approval of OWTS permit.
Systems employing new technology.
Product Development Permit.
Systems contractor license.
Regulations of systems cleaners.
Variance procedure.
General prohibitions.
Prohibition of on -site wastewater treatment systems in unsuitable areas.
Enforcement.
Penalties.
ARTICLE V Site and Soil Evaluation
Sec. 30-5-10. Site and soil evaluation general requirements.
Sec. 30-5-20. Preliminary investigation.
Sec. 30-5-30. Reconnaissance.
Sec. 30-5-40. Detailed soil investigation.
Sec. 30-5-50. Marking of Soil Profile Pit Excavations or Percolation holes.
Sec. 30-5-60. Report and site plan.
Sec. 30-5-70. Design document.
Sec. 30-5-80. Site Protection.
Sec. 30-5-90. Qualifications for a Competent Technician.
Delete Sec. 30-5-100.
ARTICLE VI Wastewater Flow and Strength
Sec. 30-6-10. Wastewater flows.
Table 30-6-1 Single -Family Residential Design Flows
Table 30-6-2 Estimate of Average Daily Wastewater Flow and BOD5 Load Per
Person Unless Otherwise Noted
Sec. 30-6-20. Wastewater strength.
Table 30-6-3 Treatment Levels
Table 30-6-4 High Strength Wastewater
ARTICLE VII Minimum Distances Between Components of an On -Site Wastewater Treatment
System and Physical Features
Sec. 30-7-10. Minimum horizontal distances.
Sec. 30-7-20. Dry gulches, cut banks and fill areas.
Sec. 30-7-30. On -site Wastewater Treatment System design consideration and treatment
requirements - separation distances from soil treatment area.
Table 30-7-1 Minimum Horizontal Distances in Feet Between Components of
and On -Site Wastewater Treatment System Installed after November 15,
1973 and Water, Physical and Health Impact Features
Table 30-7-2 On -site Wastewater Treatment System Design Consideration
and Treatment Requirements — Separation Distances from Soil Treatment
Area
ARTICLE VIII Design Criteria - General
Sec. 30-8-10. Performance.
Sec. 30-8-20. Reliability.
Sec. 30-8-30. Accessibility for inspection, maintenance and servicing.
Sec. 30-8-40. Plumbing codes.
Sec. 30-8-50. Electrical equipment.
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Sec. 30-8-60. Indicators of failure or malfunctioning for systems utilizing mechanical
apparatus.
Sec. 30-8-70. Sampling access.
Sec. 30-8-80. Component operating instructions.
Sec. 30-8-90. Surface activity.
Sec. 30-8-100. Floodplains.
Sec. 30-8-110. Business, commercial, industrial, institutional or multi -family dwelling
wastewater systems.
ARTICLE IX Design Criteria - Components
Sec. 30-9-10. Tanks and vaults.
Sec. 30-9-20. Septic tanks.
Table 30-9-1 Minimum Septic Tank Size Based on Number of Bedrooms
Sec. 30-9-30. Abandonment of tank.
Sec. 30-9-40. Pipe standards and bedding requirements.
Sec. 30-9-50. Cleanouts.
Sec. 30-9-60. Distribution Box.
Sec. 30-9-70. Drop Box.
Sec. 30-9-80. Stepdown/Relief Pipe.
Sec. 30-9-90. Wastewater Pumping and Dosing Siphon Systems.
Sec. 30-9-100. Effluent Screens.
Sec. 30-9-110. Grease Interceptor Tanks
ARTICLE X Design Criteria - Soil Treatment Area
Sec. 30-10-10. General.
Sec. 30-10-20. Calculation of infiltrative surface of soil treatment area.
Table 30-10-1 Soil Treatment Area Long-term Acceptance Rates by Soil
Texture, Soil Structure, Percolation Rate and Treatment Level
Table 30-10-1A Design Criteria for Soils with High Rock Content (Type
"R" Soils) 1, 2, 3, 4
Sec. 30-10-30. Allowable soil treatment area reductions and increases.
Table 30-10-2 Size Adjustment Factors for Methods of Application in Soil
Treatment Areas
Table 30-10-3 Size Adjustment Factors for Types of Distribution Media in
Soil Treatment Areas
Sec. 30-10-40. Design of distribution systems.
Sec. 30-10-50. Soil Treatment Area Requirements.
Sec. 30-10-60. Storage/Distribution Media.
Sec. 30-10-70. Lift stations.
Sec. 30-10-80. Soil replacement.
Sec. 30-10-90. Repairs.
ARTICLE XI Design Criteria - Higher Level Treatment Systems
Sec. 30-11-10. General.
Sec. 30-11-20. Treatment levels.
Sec. 30-11-30. Sand filters.
Sec. 30-11-40. Mound Systems.
Sec. 30-11-50. Rock plant filter (constructed wetland) treatment before soil treatment area.
ARTICLE XII Design Criteria - Other Facilities
Delete Sec. 30-12-10.
Sec. 30-12-10. Evapotranspiration and evapotranspiration/absorption systems.
Table 30-12-1 Graduation of Wicking Sand for Evapotranspiration Beds.
Delete Sec. 30-12-30.
Sec. 30-12-20. Vaults other than vault privies.
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Sec. 30-12-30. Vault Privies.
Sec. 30-12-40. Incinerating, composting and chemical toilets.
Sec. 30-12-50. Treatment systems other than those discharging through soil treatment area
or sand filter system.
ARTICLE XIII Operation and Maintenance
Sec. 30-13-10. Responsibility.
Sec. 30-13-20. Service label.
Sec. 30-13-30. Monitoring and sampling.
ARTICLE XIV TECHNOLOGY REVIEW AND ACCEPTANCE
Sec. 30-14-10. Technology Review and Acceptance
ARTICLE XV MATERIALS INCORPORATED BY REFERENCE
Sec. 30-15-10. Material Incorporated by Reference
APPENDIX
APPENDIX 30-A - TEXTURAL TRIANGLE DEFINING TWELVE TEXTURAL CLASSES OF
THE USDA (ILLUSTRATED FOR A SAMPLE CONTAINING 37% SAND, 45% SILT AND 18%
CLAY)
APPENDIX 30-B - SOIL CLASSIFICATION SYSTEM (SOIL -SEPARATE SIZE LIMITS)
APPENDIX 30-C - ANNUAL FREE WATER SURFACE EVAPORATION MAP OF WELD
COUNTY ADAPTED FROM NOAA TR NWS 33 UNITS: INCHES/YEAR ARTICLE I - Authority
ARTICLE I - AUTHORITY
Amend Sec. 30-1-20. Jurisdiction, Severability, Savings Clause.
A. These Regulations are promulgated by the Weld County Board of County Commissioners
under the authority of the Weld County Home Rule Charter, Section 3-8, acting as the Weld
County Board of Public Health under authority of the Weld County Home Rule Charter, and
upon the recommendation of the advisory Board of Public Health established pursuant to
said Charter. The jurisdiction of these Regulations extends to all territories within Weld
County including all incorporated and unincorporated areas.
B. thru E. — No change.
F. Chapter coverage. These Regulations adopted by the Weld County Board of Public Health,
pursuant to current On -site Wastewater Treatment System Regulations of the Colorado
Department of Public Health and Environment, Water Quality Control Commission,
Regulation #43 (5 CCR 1002-43) and adopted in compliance with Section 25-10-104, C.R.S.,
shall govern all aspects of permits, performance, location, construction, alteration, installation
and use of On -site Wastewater Treatment Systems of less than or equal to two thousand
(2,000) gallons per day design capacity. Site approval, design review and a discharge permit
from the Water Quality Control Division are required for a system with design capacity greater
than two thousand (2,000) gallons per day average flow.
Amend Sec. 30-1-30. Effective date.
Upon adoption, the Regulations shall become effective upon the twelfth day of February,
2018. Until the twelfth day of February, 2018, Chapter 30 Code provisions in effect prior to the
changes contained in these Regulations shall remain in effect.
ARTICLE II - Scope and Purpose
Amend Sec. 30-2-10. Declaration.
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A. — No change.
B. This regulation will apply to On -site Wastewater Treatment Systems as defined in Article Ill
of this Chapter.
Amend Sec. 30-2-30. Effluent discharged to surface waters.
Any system that will discharge into surface waters must be designed by a professional
engineer. The discharge permit application must be submitted for preliminary approval to the
Board of Public Health. Once approved by the Board of Public Health, the application must be
submitted to the Water Quality Control Division for review in accordance with the Water Quality
Control Act, Section 25-8-101, et seq., C.R.S., and all applicable regulations of the Water Quality
Control Commission. Compliance with such a permit will be deemed full compliance with this
Regulation.
ARTICLE III - Definitions
Amend Sec. 30-3-10. Definitions.
The following definitions shall apply in the interpretation and enforcement of these
Regulations. The words "shall", and "must" as used herein, indicates a mandatory requirement.
Accessible means easily reached, attained or entered by the necessary equipment or
maintenance provider.
Basal Area means the effective surface area available to transmit the treated effluent from the
filter media in a mound system into the in -situ receiving soils. The perimeter is measured at the
interface of the imported fill material and in -situ soil. On sloping sites, only the area down -gradient
from the up -slope edge of the distribution media may be included in this calculation.
Bed means a below -grade soil treatment area with a level sub -base, consisting of a shallow
excavation greater than three (3) feet wide containing distribution media and more than one (1)
lateral.
Bedroom means, a room with an egress window, a closet, and/or is intended for sleeping
purposes; or as defined by the local board of health, as stated in the local OWTS regulation.
Cistern means an underground, enclosed unpressurized reservoir or tank for storing water
as part of a potable water supply system.
Colorado Plumbing Code means Rules and Regulations of the Colorado State Plumbing
Board (3 CCR 720-1).
Competent technician means a person who has the appropriate expertise and is able to
conduct and interpret the results of soil profile test pit excavations, percolation tests, and site
evaluations. This individual has also met the required competencies for a "Competent
Technician" as defined in Section 30-5-90.
Composting toilet means a self-contained waterless toilet designed to decompose non -water -
carried human wastes through microbial action and to store the resulting matter for disposal.
Consistence means the degree and kind of cohesion and adhesion that soil exhibits and/or
the resistance of soil to deformation or rupture under an applied stress to an extent that the soil
density would restrict soil permeability. Aspects of consistence are used to determine if the
horizon will have permeability lower than that of the defined soil type. Additional insight to
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consistence can be found in the USDA - NRCS Field book for Describing and Sampling Soils;
Version 3.0, Sept. 2012.
Cut -bank means a nearly vertical slope caused by erosion or construction that has exposed
historic soil strata.
Deep gravel system means a soil treatment area for repairs only where the trenches utilize a
depth of gravel greater than six (6) inches below the distribution pipe and sidewall area is allowed
according to a formula specified in this Regulation.
Deficiency. See Malfunction.
Distribution box means a watertight component that receives effluent from a septic tank or
other treatment unit and distributes effluent via gravity in approximately equal portions to two (2)
or more distribution laterals in the soil treatment area.
Domestic wastewater treatment works means a system or facility for treating, neutralizing,
stabilizing or disposing of domestic wastewater, which system or facility has a designed capacity
to receive more than two thousand (2,000) gallons of domestic wastewater per day. The term
domestic wastewater treatment works also includes appurtenances to such system or facility,
such as outfall sewers and pumping stations, and to equipment related to such appurtenances.
Domestic wastewater treatment works does not include industrial wastewater treatment plants or
complexes whose primary function is the treatment of industrial wastes, notwithstanding the fact
that human wastes generated incidentally to the industrial process are treated therein. Section
25-8-103(5), C.R.S.
Dosing, pressure means a uniform application of wastewater throughout the intended portion
of the soil treatment area through small diameter pipes and orifices, under pressure. For this
definition, the term pressure indicates that the system is capable of creating upward movement
of effluent out of the distribution system piping.
Effective size means the size of granular media such that ten percent (10%) by weight of the
media is finer than the size specified.
Effluent pipe means nonperforated pipe that conveys effluent from one (1) On -site
Wastewater Treatment System component to the next.
Delete Experimental system.
Failure means a condition existing within any component of an OWTS which prevents the
system from functioning as intended, and which results in the discharge of untreated or partially
treated wastewater onto the ground surface, into surface water or ground water, or which results
in the back-up of sewage into the building sewer. Other conditions within an OWTS component
that are deemed by a local public health agency to be a threat to public health and/or safety
may also be deemed a failure.
Floodplain, 100 -year means an area adjacent to a stream which is subject to flooding as the
result of the occurrence of a one -hundred -year flood, and is so adverse to past, current or
foreseeable construction or land use as to constitute a significant hazard to public or
environmental health and safety or to property, or is designated by the Federal Emergency
Management Agency (FEMA) or National Flood Insurance Program (NFIP). In the absence of
FEMA/NFIP maps, a professional engineer must certify the floodplain elevations.
Floodway means the channel of a river or other watercourse and the adjacent land areas that
must be reserved in order to discharge the base flood without cumulatively increasing the water
6
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surface elevation more than one-half (141/2) foot (six [6] inches) at any point or as designated by
the Federal Emergency Management Agency or National Flood Insurance Program. In the
absence of FEMNNFIP maps, a professional engineer must certify the floodway elevation and
location.
Flow, design means the estimated volume of wastewater per unit of time for which a
component or system is designed. Design flow may be given in the estimated volume per unit,
such as person per unit time, that must be multiplied by the maximum number of units that a
facility can accommodate over that time.
Higher level treatment means designated treatment levels other than treatment level 1. (See
Table 30-6-3).
Holding tank. See vault.
Infiltrative surface means designated interface where effluent moves from distribution media
or a distribution product into treatment media or original soil. In standard trench or bed systems
this will be the interface of the distribution media or product and in -situ soil. Two separate
infiltrative surfaces will exist in a mound system and an unlined sand filter; one at the interface of
the distribution media and fill sand, the other at the interface of the fill sand and in -situ soil.
Lateral means a pipe, chamber or other conveyance used to carry and to distribute effluent.
Delete Limiting condition.
Limiting layer means a horizon or condition in the soil profile or underlying strata that limits
the treatment capability of the soil or severely restricts the movement of fluids. This may include
soils with low or high permeability, impervious or fractured bedrock, or a seasonal or current
ground water surface.
Linear Loading Rate means the amount of effluent applied per linear foot along the contour
(gpd/linear ft.).
Liner means an impermeable synthetic or natural material used to prevent or restrict
infiltration and/or exfiltration. For the purposes of this regulation, the minimum thickness of a liner
must be 30 ml.
Long -Term Acceptance Rate (LTAR) means a design parameter expressing the rate that
effluent enters the infiltrative surface of the soil treatment area at equilibrium, measured in volume
per area per time, e.g. gallons per square foot per day (gal/ft 2/day).
Malfunction means the condition in which a component is not performing as designed or
installed and is in need of repair in order to function as originally intended.
Manufactured media. See Media, other manufactured.
Media, Enhanced Manufactured means an accepted proprietary manufactured distribution
product, other than a chamber, wrapped in a specified fabric, and placed on a specified sand
base or media that does not mask the infiltrative surface of the in -situ soil.
Media, other manufactured means an accepted proprietary manufactured distribution product
made of synthetic media for distribution of effluent that is placed directly on the in -situ soil.
Mound means a soil treatment area whereby the infiltrative surface is at or above original
grade at any point.
Pressure distribution. See Dosing, pressure.
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Record Drawing means construction drawings provided to illustrate the progress or
completion of the installation of an OWTS, or components of the OWTS; typically based on field
inspections by the designer or local public health agency.
Remediation system means a treatment system, chemical/biological additive or physical
process that is proposed to restore the soil treatment area of an OWTS to intended performance.
Repair means restoration of functionality and/or treatment by reconstruction, relocation, or
replacement of an on -site sewage wastewater treatment system or any component thereof in
order to allow the system to function as intended.
Delete Restrictive layer
Replacement System. See Repair.
Sand filter means an engineered designed OWTS that utilizes a layer of specified sand as
filter and treatment media and incorporates pressure distribution.
Sand filter, lined means an engineered designed OWTS that has an impervious liner and
under -drain below the specified sand media. Lined sand filters may be intermittent/single pass,
where the effluent is distributed over the sand bed a single time before distribution to a soil
treatment area, or recirculating, where part of the effluent is returned to an earlier component for
additional treatment before distribution to a soil treatment area.
Sand filter, unlined means an engineered designed OWTS that includes a layer of specified
sand used as a treatment media without a liner between the sand and the existing soil on which
it is placed.
Sequential distribution means a distribution method in which effluent is loaded into one (1)
trench and fills it to a predetermined level before passing through a relief pipe or device to the
succeeding trench. The effluent does not pass through the distribution media before it enters
succeeding trenches.
Serial distribution means a distribution method in which effluent is loaded into one (1) trench
and fills it to a predetermined level before passing through a relief pipe or device to the succeeding
trench. The effluent passes through the distribution media before entering succeeding trenches
which may be connected to provide a single uninterrupted flow path.
Delete Soil profile hole.
Soil profile test pit excavation means a trench or other excavation used for access to evaluate
the soil horizons for properties influencing effluent movement, bedrock, evidence of seasonal high
groundwater and other information to be used in locating and designing an On -site Wastewater
Treatment System -AIM.
Soil treatment area means the physical location where final treatment and dispersal of
effluent occurs. Soil treatment area includes drainfields, mounds and drip fields.
Suitable soil means a soil which will effectively treat and filter effluent by removal of
organisms and suspended solids which meets long-term acceptance rate requirements as defined
in Table 30-10-1, and has the required vertical thickness below the infiltrative surface and above
a limiting layer.
Volume, effective means the amount of effluent contained in a tank under normal operating
conditions; for a septic tank, effective volume is determined relative t0 the invert of the outlet.
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For a dosing tank, the effective volume under normal conditions is determined relative to the invert
of the inlet and the control off level.
Wastewater, high strength means:
1. Wastewater from a structure having BOD 5 greater than three hundred (300) mg/L;
and/or TSS greater than two hundred (200) mg/L; and/or fats, oils and grease greater
than fifty (50) mg/L; or
2. Effluent from a septic tank or other pretreatment component (as defined by NSF/ANSI
Standard 40 testing protocol) that has BOD 5greater than one hundred eighty (180) mg/L;
and/or TSS greater than eighty (80) mg/L; and/or fats, oils and grease greater than
twenty-five (25) mg/L and is applied to an infiltrative surface.
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Amend Sec. 30-3-20. Abbreviations and acronyms.
Amend Table 30-3-1 Abbreviations and Acronyms
Abbreviation/Acronym
AASHTO
ANSI
ASTM
BOD
C.R.S.
CBOD
CSA
gpd
IAPMO
ISDS
LTAR
mg/L
MPI
NAWT
NDDS
NPCA
NSF
OWTS
Full Title
American Association of State Highway and Transportation Officials
American National Standards Institute
American Society for Testing and Materials
Biochemical Oxygen Demand
Colorado Revised Statutes
Carbonaceous Biochemical Oxygen Demand
Canadian Standards Association
gallons per day
International Association of Plumbing and Mechanical Officials
Individual Sewage Disposal System
milligrams per liter
Minutes per Inch
National Association of Wastewater Technicians
Non -pressurized Drip Dispersal System
National Precast Concrete Association
National Sanitation Foundation
On -site Wastewater Treatment System
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STA Soil Treatment Area
Treatment Level
Total Nitrogen
Total Suspended Solids
Underwriters' Laboratories
ARTICLE IV - Administration and Enforcement
Amend Sec. 30-4-30. Permit application requirements and procedures.
A. thru C.13. — No changes.
14. Other information, data, plans, specifications and tests as required by the Division,
including but not limited to:
a. Additional evaluation: When the Division representative has determined that the
Division does not have sufficient information for evaluation of an application or a
system, the Division representative may require additional tests or documentation.
b. Additional hydrological, geological or engineering: When specific evidence suggests
undesirable soil conditions exist, additional hydrological, geological, engineering or
other information provided by a professional engineer or geologist may be required
to be submitted by the applicant. This requirement will not prejudice the right of the
Division to develop its own information from its own sources.
c. Any expenses associated with additional information, data, plans, specifications and
tests shall be the responsibility of the party obtaining the permit.
D. and E. — No change.
F. Other fees.
1. Reinspection fee. The Division may assess a reinspection fee as established by the
Board of County Commissioners for each inspection or reinspection when such portion
of work for which inspection is called is not complete or when corrections called for are
not ready.
2. Surcharge. The Division must collect a fee of twenty-three dollars ($23.00) for each
permit issued for a new, repaired or upgraded OWTS. Of that fee, the Division must
retain three dollars ($3.00) to cover the Division's administrative costs and twenty dollars
($20.00) must be transmitted to the State Treasurer, who must deposit that sum in the
Water Quality Control Fund created in Section 25-8-502(1)(c), C.R.S.
G. and H. — No change.
I. A permit must be required for the expanded use of an OWTS. The OWTS must be replaced
or modified to handle the increased design flow unless it is determined that the existing
system is adequately designed and constructed for the higher design flow rate.
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J. The issuance of a permit and specification of terms and conditions therein will not constitute
assumption of liability nor create a presumption that the County or its officers, employees or
agents may be liable for the failure or malfunctioning of any system. Permit issuance will not
constitute a certification that the system, the equipment used in the system, or any
component used for system operation will ensure continuous compliance with the provision
of the OWTS Act, applicable sections of these Regulations adopted thereunder or any terms
and conditions of a permit.
Remainder of Section — No change.
Amend Sec. 30-4-40. Determination of compliance of permit submission.
A. and B. — No change.
C. No permits shall be issued for the following systems unless they are designed by a
professional engineer and until they have been reviewed and approved by the Board of Public
Health:
1. Product Development Permits.
2. Treatment systems other than those discharging through a soil treatment area or a sand
filter system.
Amend Sec. 30-4-80. Final approval of OWTS permit.
A. Final approval of the OWTS permit by the Division must include, but is not limited to:
1. Receipt of letter from the professional engineer certifying construction of the OWTS as per
the approved design, if the OWTS was engineer -designed;
2. Receipt of a record drawing which includes a scale drawing showing all components of
the OWTS, including their location from known and findable points, dimensions, depths,
sizes, manufacturers' names and models as available, and other information relative to
locating and maintaining the OWTS components;
3. Final inspection prior to backfilling the OWTS by the Division, confirming that it was
installed according to the permit requirements and regulations or variances to the
regulations; and
4. Identification of the systems contractor.
Amend Sec. 30-4-90. Systems employing new technology.
Systems employing new technology may be considered by the Division, provided they have
been reviewed and accepted by the Water Quality Control Division according to Section 43.13 of
On -site Wastewater Treatment System Regulation #43, as adopted in 2017. The Division
prohibits the reduction of system size, or the reduction in vertical or horizontal separation when
higher level treatment systems are used.
Delete Sec. 30-4-100. - Experimental systems in its entirety and replace with the following:
Sec. 30-4-100. Product Development Permit
A. For products that have not received Colorado Water Quality Control Division acceptance, the
manufacturer may apply to the local public health agency for a product development permit.
Requirements for proprietary treatment component acceptance are in Regulation 43-5 CCR
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1002-43. The Division prohibits the reduction of system, size, or the reduction in vertical or
horizontal separation when higher level treatment systems are used.
B. For products or types of systems which have not been otherwise accepted by the Colorado
Water Quality Control Division pursuant to section 43.13.D of Regulation 43, the Board of
Public Health may approve an application for product development permit only if the system
has been designed by a professional engineer, and only if the application provides proof of
the ability to install a replacement OWTS in compliance with all local requirements in a timely
manner in the event of a failure or malfunction of the system installed.
C. Before a product development permit is issued, the Water Quality Control Division must
determine that the product to be tested qualifies for testing under the product development
evaluation based on information submitted to the Division.
1. Applicant must provide evidence of nationally accepted third -party testing of the product
to be evaluated, or
2. Provide test data from multiple single-family homes under normal working conditions that
meet the following criteria:
a. Test data must be provided from a minimum of four sites.
b. Each system must be tested over a period of at least one year.
c. Each system must be sampled at least three times during the year with at least one
sample obtained during cold weather conditions.
d. Laboratory results for all parameters for which acceptance is being requested must be
submitted.
D. The board of health must not arbitrarily deny any person the right to consideration of an
application for such a system and must apply reasonable performance standards in
determining whether to approve such an application; 25-10-108 (2), C.R.S.
E. A completed application for a product development permit must be submitted to the Division
at least 30 days in advance of installation of the product.
F. An application for a product development permit must include the following:
1. Proof of the ability to install a replacement OWTS in compliance with all local requirements
in a timely manner in the event of a failure or malfunction of the system under testing;
2. A description of the product under development including performance goals;
3. Documentation signed by the owner of the proposed product development site allowing
access to the local public health agency and Division for inspection of the site; and,
4. Design documents as required in section 30-5-70 of this regulation.
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G. Other than the performance standards identified in section 30-4-100 C. 2 above, the division
may stipulate additional requirements for the product development permit necessary to ensure
that the system performs as intended.
H. A product development permit is a site -specific permit. Product development testing at
multiple sites requires a product development permit for each site.
I. During the term of the product development permit, all data collected is to be submitted to the
Water Quality Control Division and the Division.
J. The Division may revoke or amend a product development permit, if the continued operation
or presence of the product under development:
1. Presents a risk to the public health or environment;
2. Causes adverse effects on the proper function of the OWTS on the site;
3. Leaks or discharges effluent on the surface of the ground; or
4. If the developer of the product fails to comply with any requirements stipulated on the
permit by the Division or the Water Quality Control Division.
K. If the product development permit is revoked, the product developer must install the
replacement system.
L. Once the system is installed and approved, the Division must supply the Water Quality Control
Division with a copy of the completed OWTS permit.
M. The Division prohibits the reduction of system size, or the reduction in vertical or horizontal
separation when higher level treatment systems are used.
Amend Sec. 30-4-110. Systems Contractor License.
A. No person, except as in Section 30-4-110.B below, shall install, engage in the installation of,
or repair an OWTS unless such person holds a valid systems contractor license issued by the
Division. Employees of a validly licensed Systems Contractor shall not be required to be
licensed. The initial fee for a systems contractor license shall be set by separate Chapter of
the Board of Weld County Commissioners. A license shall expire on December 31 of each
year, and shall be renewed within thirty (30) days prior thereto, and an annual renewal fee, as
set by separate Chapter of the Board of Weld County Commissioners, shall be charged. A
license which lapses because of failure to renew or is revoked shall be subject to the fee
established for a new license upon re -application.
Remainder of Section — No change.
Amend Sec. 30-4-130. Variance procedure.
A. and B. — No changes.
C. Variances for repair of failing systems.
1. — No change.
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2. For the repair of or upgrade to an existing system where the existing system does not
meet the required separation distances and where the conditions other than lot size
precludes adherence to the required distances, a variance to the separation distances
may be requested. The repairs or upgrade must be no closer to features requiring
setbacks than the existing facilities. Variances requesting setbacks no closer than
existing setbacks do not have to provide technical justification from a professional
engineer or professional geologist.
D. Prohibitions on the granting of variance requests.
1. and 2. — No change.
3 No variance will be issued which will result in setbacks to an offsite physical feature
which do not conform to the minimum setbacks defined in Table 30-7-1 without the board
of health considering any concerns of the owner of property containing said feature.
Property lines are considered offsite features. The property owner containing said
feature must be notified of the time and date of the hearing.
4. thru 6. — No change.
7. No variance shall be issued for the installation of a higher level treatment system based
on sizing or separation reductions.
Remainder of Section — No change.
Amend Sec. 30-4-140. General prohibitions.
A. — No change.
B. Use, construction or existence of cesspools, pit privies, slit trenches, and seepage pits, is
prohibited.
Remainder of Section — No change.
Amend Sec. 30-4-160. Enforcement.
A. — No change.
B. Cease and desist orders. The Health Officer or his or her designee may issue an order to
cease and desist from the use of any OWTS or sewage treatment works which is found by
the Health Officer not to be functioning in compliance with these Regulations, the OWTS Act
or with applicable regulations, or is found to constitute a hazard to public health or has not
otherwise received timely repairs under the provisions of Section 25-10-106(1)0), C.R.S.
Such an order may be issued only after a hearing which shall be conducted by the Health
Officer not less than forty-eight (48) hours after written notice thereof is given to the owner or
occupant of the property on which the system is located. The order shall require that the
owner or occupant bring the system into compliance or eliminate the health hazard within
thirty (30) days, or thereafter cease and desist from the use of the system. A cease and desist
order issued by the Health Officer shall be reviewable in the district court for the County
wherein the system is located and upon a petition filed not later than ten (10) days after the
order is issued.
Amend Sec. 30-4-170. Penalties.
A. and B. — No change.
C. Upon a finding by the local board of health that a person is in violation of this regulation, the
local board of health may assess a penalty of up to fifty dollars for each day of violation. In
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determining the amount of the penalty to be assessed, the local board of health shall consider
the seriousness of the danger to the health of the public caused by the violation, the duration
of the violation, and whether the person has previously been determined to have committed
a similar violation.
D. A person subject to a penalty assessed pursuant to section 30-4-170 B. may appeal the
penalty to the local board of health by requesting a hearing before the appropriate body. The
request must be filed within thirty days after the penalty assessment is issued. The local
board of health shall conduct a hearing upon the request in accordance with section 24-4-
105, C.R.S.
ARTICLE V - Site and Soil Evaluation
Amend Sec. 30-5-10. Site and soil evaluation general requirements.
A. A site and soil evaluation must be conducted for each property on which an OWTS is
proposed, to determine the suitability of a location to support an OWTS and to provide the
designer with a sound basis to select the most appropriate OWTS design for the location and
application. Each site evaluation must consist of:
1. Preliminary investigation;
2. Reconnaissance;
3. Detailed soil investigation; and
4. Report and site plan.
Amend Sec. 30-5-20. Preliminary investigation.
A. Preliminary investigation: Research of information relative to the site and anticipated
conditions must be conducted. Information gathered as part of the preliminary investigation must
include, but is not limited to:
1. Property information:
a. Address;
b. Legal description;
c. Existing structures; and
d. Location of existing or proposed wells on the property.
2. Existing Division OWTS records.
3. Published site information:
a. Topography; and
b. Soil data.
4. Location of physical features, on and off the property, that will require setbacks, as
identified in Table 30-7-1.
5. Preliminary soil treatment area size estimate based on information on existing or planned
facility and local regulations.
6. Other information required by the Division.
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7. Additional information that may be useful to the specific evaluation, as available:
a. Survey;
b. Easements;
c. Floodplain maps;
d. Geology and basin maps and descriptions;
e. Aerial photographs;
f. Climate information; and
g. Delineated wetlands maps.
Amend Sec. 30-5-30. Reconnaissance.
A. Reconnaissance: A visit to the property to evaluate the topography and other surface
conditions that will impact the location and design of the OWTS must be conducted.
Information gathered as part of the site reconnaissance may include, but is not limited to:
1. Landscape position;
2. Topography;
3. Vegetation;
4. Natural and cultural features; and
5. Current and historic land use.
Amend Sec. 30-5-40. Detailed soil investigation.
A. Soil investigations to determine the long-term acceptance rate of a soil treatment area must
be conducted per the following criteria:
1. Visual and tactile evaluation of two (2) or more soil profile test pit excavations must be
conducted to determine soil type as well as to determine whether a limiting layer is
encountered.
2. In addition to the two soil profile test pit excavations, percolation testing may be
conducted to obtain additional information regarding the long-term acceptance rate of
the soil.
3. If the site evaluation includes both a visual tactile evaluation of soil profile test pit
excavations and percolation tests, and the results from these two evaluations do not
coincide with the same LTAR as noted in Table 30-10-1, the designer must use the more
restrictive LTAR in determining the size of the soil treatment area.
B. Procedure for performing visual and tactile evaluations of soil in order to determine a long-
term acceptance rate:
1. The soils evaluation shall be performed by or under the supervision of a professional
engineer, professional geologist, competent technician, or other similarly qualified
professional as approved by the Division.
2. Evaluation of two (2) or more soil profile test pit excavations must be performed to
determine soil types, limiting layers, and best depth for the infiltrative surface. The total
number of soil profile test pit excavations beyond the required two shall be based on the
judgment of the competent technician.
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3. At least one (1) of the soil profile test pit excavations must be performed in the portion of
the soil treatment area anticipated to have the most limiting conditions.
4. The minimum depth of the soil profile test pit excavation must be to any limiting layer, or
four feet below the infiltrative surface of the in -situ soil, whichever is encountered first.
5. Layers and interfaces that interfere with the treatment and dispersal of effluent must be
noted. Thus, any limiting soil characteristic such as consistence also needs to be
evaluated. The evaluation of consistence may also include an evaluation of excavation
difficulty, rupture resistance, and/or penetration resistance.
6. The soil observations must be conducted at or immediately adjacent to the location of
the proposed soil treatment area, but if possible, not under the final location of a trench
or bed.
7. Each soil profile test pit excavation observed at the proposed soil treatment area must
be evaluated under adequate light conditions with the soil in an unfrozen state.
8. The soil observation method must allow observation of the different soil horizons that
constitute the soil profile.
9. Soil profile test pit observations must be conducted prior to percolation tests to determine
whether the soils are suitable to warrant percolation tests and, if suitable, at what depth
percolation tests must be conducted.
10. The soil type at the proposed infiltrative surface of the soil treatment area or a more
restrictive soil type within the treatment depth must be used to determine the long-term
acceptance rate from Table 30-10-1 or Table 30-10-1A. The treatment depth is two to
four feet depending on the required thickness for the treatment level below the infiltrative
surface from Item 4, Table 30-7-2.
11. Soils data, previously collected by others at the site can be used for the purposes of an
OWTS design at the discretion of the local public health agency. It is recommended that
the data be verified, at a minimum, by performing an evaluation of a soil profile test pit
excavation.
C. Soil descriptions for determination of a limiting layer must include:
1. The depth of each soil horizon measured from the ground surface and a description of
the soil texture, and structure of each soil horizon;
2. Depth to the bedrock;
3. Depth to the periodically saturated soil as determined by:
a. Redoximorphic features and other indicators of water levels; or
b. Depth of standing water in the soil observation excavation, measured from the
ground surface, if observed, unless redoximorphic features indicate a higher level.
D. Procedure for performing percolation tests:
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1. — No change.
2. Number of test holes; Location.
a. Soil percolation tests shall be performed in at least three (3) test holes in the area
in which the soil treatment area is to be located, spaced evenly over the proposed
area.
b. If the likely depth of a proposed infiltrative surface is uncertain, percolation tests
must be performed at more than one (1) depth to determine the depth of the
infiltrative surface.
3. Dimensions.
a. The percolation test hole must have a diameter of eight (8) to twelve (12) inches and
be terminated a minimum of six (6) inches and a maximum of eighteen (18) inches
below the proposed infiltrative surface.
4. Change in soil.
a. If a change of soil type, color or structure is present within those soils comprising the
depth of soil below the infiltrative surface as required in Table 30-7-2 for vertical
separation, a minimum of two (2) soil percolation holes must be terminated in the
changed soil and percolation tests must be conducted in both holes.
5. Percolation tests.
a. The percolation tests must be conducted using the hole preparation, soil saturation
and rate measurement procedures described below.
b. — No change.
c. Presoak.
1) The hole must be presoaked adequately to accomplish both saturation, which
is filling the void spaces between the soil particles, and swelling, which is the
intrusion of water into the individual soil particles.
2) — No change.
d. Percolation rate measurement.
1) With the exception of sandy soils containing five percent (5%) or less particles
passing through the #200 sieve, by weight, percolation rate measurements
must be made on the day following the presoak procedure.
2) If water remains in the percolation test hole after the swelling period, adjust the
depth to approximately six (6) inches above the gravel in the bottom of the hole.
From a fixed reference point, measure the drop in water level over thirty -minute
intervals. The drops are used to calculate the percolation rate.
3) — No change.
e. Sandy soils.
1) In sandy soils or other soils in which the first six (6) inches of water seeps out
of the hole in less than thirty (30) minutes, after the twenty-four (24) hour
swelling period, the time interval between measurements must be ten (10)
minutes and the test conducted for one (1) hour. The drop that occurs during
the final ten (10) minutes must be used to calculate the percolation rate.
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2) If the soil is so sandy or coarse textured that it will not retain any water, then
the infiltration rate must be recorded as less than one (1) minute per inch.
f. Percolation rate determination and reporting.
1) The field percolation rate will be the average rate of the percolation rates
determined for all percolation test holes observed in the proposed soil treatment
area in minutes per inch. The average percolation rate determined by the tests
must be used in determining the long-term acceptance rate for the proposed
system from Table 30-10-1.
2) The technician performing the percolation tests shall furnish an accurate scale
drawing, showing the location of the soil profile test pit excavations and/or
percolation holes tied to lot corners or other permanent objects. The drawing
must meet the criteria in Paragraph 30-5-60.A.7. All holes must be clearly
labeled to relate to the information provided for the profile test pits and
percolation tests.
g. Alternate percolation testing.
1) Alternate percolation test procedures may be approved, provided that the test
results of alternate procedures are substantially equivalent to those determined
using the test procedures described in this Section.
2) Prior approval from the Division of alternate percolation test procedures is
required.
Delete E. and F. in its entirety.
Amend Sec. 30-5-50. Marking of Soil Profile Test Pit Excavations or Percolation holes.
The soil profile test pit excavations or percolation holes, must be flagged or otherwise marked
to allow easy location by others. Percolation holes must remain open until after evaluation by the
Division. The soil profile test pit excavations may be backfilled after evaluation by the third party
professional (professional engineer, geologist, competent technician or other similar
professional). If the profile test pit excavation is backfilled prior to inspection by the Division, a
monitoring port shall be installed prior to backfilling for evaluation by the Division. Soil test pit
excavations that are left open must be suitably barricaded to prevent unauthorized access and to
address safety concerns.
Amend Sec. 30-5-60. Report and site plan.
A. A written report must describe the results of the preliminary investigation, reconnaissance
and detailed evaluations. The report may be in text and/or tabular form and must include a
drawing locating features relative to the proposed OWTS location and test locations. The
report may be included as part of the OWTS design document. The report must include, but
is not limited to:
1. Company name, address, telephone number, e-mail address and name of individual,
credentials and qualifications of the individual conducting the site evaluation;
2. Preliminary and detailed evaluations, providing information from the surface site
characteristics assessment and soils investigation;
3. Dates of preliminary and detailed evaluations;
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4. A graphic soil log, to scale, indicating depth of the soil test pit excavation, soil description
and classification, depth to any limiting layer encountered , type of equipment used to
excavate the soil profile test pit, and date of soils investigation;
5. Setback distances to features listed in Table 30-7-1;
6. Setback distances to features listed in Table 30-7-2, existing on the site or within
applicable setback limits, whichever is greater;
7. A drawing created to a scale that provides the complete property boundary lines. The
minimum drawing size is eight and one-half (8.5) inches by eleven (11) inches. If the
property is too large to adequately indicate and label the profile test pits and percolation
test holes, a detail of the portion of the site containing the soil profile test pits and
percolation test holes must be submitted. If the property is too large to adequately show
site evaluation information, a detail drawing that includes the information required from
the site and soil evaluation that will impact the location of the OWTS must be submitted.
Drawings must indicate dimensions, have a north arrow and graphic scale and include:
a. Fixed, non -degradable temporary or permanent benchmark, horizontal and vertical
reference points of the proposed soil treatment area; soil observations; percolation
testing results and pertinent distances from the proposed OWTS to all required
setbacks, lot improvements, easements, ordinary high water mark of a pond, creek,
stream, lake, wetland or other surface waters and detention or retention ponds; and
property lines;
b. Contours or slope direction and percent slope;
c. The location of any visible or known unsuitable, disturbed or compacted soils;
d. The estimated depth of periodically saturated soils and bedrock or flood elevation,
if applicable; and
e. The proposed elevation of the infiltrative surface of the soil treatment area, from an
established datum (either ground surface or a benchmark).
8. Anticipated construction -related issues, if applicable;
9. An assessment of how known or reasonably foreseeable land use changes are expected
to affect the system performance, including but not limited to changes in drainage
patterns, increased impervious surfaces and proximity of new water supply wells, if
applicable; and
10. A narrative explaining difficulties encountered during the site evaluation, including but
not limited to identifying and interpreting soil and landform features and how the
difficulties were resolved, if applicable.
Amend Sec. 30-5-70. Design document.
A. The report and site plan may be attached to the design document or the report and site plan
may be combined with the design information as a single document.
B. The design document must include a brief description of the facility and its proposed use,
basis and calculations of design flow and influent strength.
C. The design document must contain all plan detail necessary for permitting, installation and
maintenance, including:
1. Assumptions and calculations for each component, including total dynamic head (TDH)
and gallons per minute (GPM) for all dosing systems;
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2. A fixed, non -degradable temporary or permanent benchmark, (North America Vertical
Datum or assumed elevation is acceptable);
3. A scale drawing showing the location of each OWTS component and distances to water
supplies, surface water, physical and health impact features on both the subject and
adjacent properties requiring setbacks;
4. Layout of soil treatment area, dimensions of trenches or beds, distribution method and
equipment, distribution boxes, drop boxes, valves or other components used;
5. Elevation or depth of infiltrative surface of the soil treatment area, the septic tank invert,
and all other components of the OWTS;
6. Special structural design considerations, as applicable to ensure the long-term integrity
of each component;
7. References to design manuals or other technical materials used;
8. Installation procedures, as applicable;
9. Operation and maintenance manuals or instructions; and
10. Other information that may be useful, such as photos and cross-section drawings.
Amend Sec. 30-5-80. Site protection.
Prior to and during construction, the proposed soil treatment area and replacement area, if
any, must be protected from disturbance, compaction or other damage by means of staking,
fencing, posting or other effective method.
Amend Sec. 30-5-90. Qualifications for competent technician.
A. — No change.
B. Visual and tactile evaluation of soil.
1. Competencies needed:
a. and b. — No change.
c. Identify type and grade of soil structure;
d. thru g. — No change.
2. Possible demonstrations of competence in visual and tactile evaluation of soil:
a. — No change.
b. Attendance at training or workshop for soil evaluation for OWTS, including both class
and field work.
(1) If the training or workshop includes an exam to verify acceptable completion of
the course, a passing grade on the exam must be attained.
3. The Water Quality Control Division must approve training for visual and tactile evaluation
of soil.
ARTICLE VI - Wastewater Flow and Strength
Amend Sec. 30-6-10. Wastewater flows.
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A. — No change.
B. Single-family residential homes.
1. Design flow per person must be seventy-five (75) gallons per day (gpd).
2. The minimum design flow for a new home must be for a two -bedroom house, unless
otherwise noted in this regulation. The minimum design flow for the repair or replacement
of an OWTS of an existing one -bedroom home must be for one -bedroom, unless
bedrooms are added.
3. For homes up to and including three (3) bedrooms, the assumed number of persons per
bedroom is two (2) for design purposes.
4. For homes with more than three (3) bedrooms, the assumed number of persons is six
(6) persons (first three [3] bedrooms x two [2] persons per bedroom), plus one (1)
additional person for each bedroom more than three (3) bedrooms.
5. — No change.
Table 30-6-1 — No change.
C. Auxiliary buildings.
1. — No change.
2. If the flow from the auxiliary building is only generated by residents of the home, it will
be assumed that the OWTS for the home will be adequately sized to include the auxiliary
building if the flows are combined.
3. — No change.
4. If the auxiliary building has a separate OWTS, the facility must be sized on the basis of
Table 30-6-2 and a septic tank detention time of forty-eight (48) hours.
D. Multi -family and commercial on -site wastewater treatment systems.
1. Design flow values and strengths for multi -family and commercial systems must be
determined from:
a. Table 30-6-2; or
b. An analysis of flows and strengths from at least three (3) comparable facilities or from
the facility, if it is an existing facility, must be submitted to the Division for approval.
The analysis must include:
1) Metered water flows for inside use only for at least a year or, if the use is seasonal,
for a full season. If metered flows are less than full capacity, they must be paired
with actual use in units of persons present or meals served or other units as
appropriate so that an actual daily rate per unit can be determined. The daily rate
per unit times the number of units at full occupancy will be the design flow.
2) Total suspended solids and BOD 5 or CBOD 5 tests at times of full use. At least
three (3) samples, taken at least one (1) week apart, are required. Sampling that
provides equivalent and representative data through "composite sampling" may be
allowed.
3) Explanation and justification for the comparability of the tested facilities with the
proposed facility.
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E. Flow equalization.
1. — No change.
2. The highest peak assumed must be at least equal to the full capacity of the facility.
3. The stored flow must be distributed to the soil treatment area before the next greater -
than -average peak.
4. — No change.
5. Timed dosed pressure distribution or timed dosed NDDS must be used. The soil
treatment area reduction for pressure distribution must not be used in addition to the flow
equalization reduction.
6. — No change.
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Amend Table 30-6-2
Estimate of Average Daily Wastewater Flow and
BOD 5 Load Per Person Unless Otherwise Noted
GPD
Residential Wastewater
Single-family dwellings 75
Auxiliary buildings by fixture type
Bath/shower
Dishwasher
. . ....._.. _........ .
Kitchen sink with garbage grinder
Laundry washer
Water closet (toilet)
Hotels and motels per room
Multiple -family dwellings or apartments
Boarding and rooming houses (users absent during working hours)
Tiny Homes***, per unit
Mobile home
Mobile home park per space
Commercial Wastewater
BOD 5 in
Pounds Per
Day
8.4 .021
150 .40
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Facilities with short-term or transient visitors
Examples: Airports or bus stations per passenger; fairgrounds per
person attending; ball parks, race tracks, stadiums, theaters or
auditoriums per seat
5
Airport per employee 10
Barber and beauty shops per chair 100
Bowling alleys per lane - toilet wastes only 5
.02
.06
.70
.03 *
Country club per member 30
.02
Country club per employee
Dentist offices per non -wet chair
20 .06
50 .14 *
Doctor offices per doctor 250
Factories and plants exclusive of industrial wastewater per employee
per eight -hour shift - no showers
Factories and plants exclusive of industrial wastewater per employee
per eight -hour shift - showers provided
20
.80
.05
35
Kennels per dog 30
Laundries, self-service per commercial washer
400
Office buildings per employee per 8 -hour shift 15
.08
.20
.75
.06
Service stations per toilet fixture
250
.50
Stores and shopping centers per square foot of retail space
.01 *
Work or construction camps semi -permanent with flush toilets 50
.17
Work or construction camps semi -permanent without flush toilets 35
Food Service Establishment
.02
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Restaurant open 1 or 2 meals per seat
24 -hour restaurant per seat
Restaurant with paper service only per seat
Additional for bars and cocktail lounges per seat
Drive-in restaurant per car space
.06/meal
.07/meal served
Institutional Wastewater Without Kitchens Unless Otherwise Noted
Churches, per seat; without any food service, or other uses
Churches, per seat; warming kitchen only, no major food service �
Churches, per seat; with food service, per meal served**** = 4
Hospitals per bed space 250
Nursing homes; Group homes for developmentally disabled, per bed
space
Schools, boarding per person
Schools, day without cafeteria, gym or showers
Schools, day with cafeteria, no gym or showers
Schools, day with cafeteria, gym and showers
Schools, day additional for school workers
Recreational and Seasonal Wastewater Use
Camps, day, no meals served
Luxury resort
Resort, night and day
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Campground per campsite **
Public park flush toilet per fixture per hour when park is open
Public park urinal per fixture per hour when park is open
Public park shower per fixture per hour when park is open
Public park faucet per fixture per hour when park is open
Swimming pools and bathhouses ~ _.
i
Travel trailer p arks with individual water and sewage hookup per unit
Travel trailer park without individual water and sewage hookup per
unit -
.12
.04 lbs./fixture
.01 lbs/fixture
.10 lbs./fixture
.04 lbs./fixture
.06
* BOD levels need further verification depending on the specific use of the facility.
-Laundry facilities are to be calculated on a per -commercial washer basis in accordance with
other elements of this table.
***For the purpose of this Table, a "Tiny home" is a structure that has only one bedroom and
has <400 sq.ft. of livable space, including lofts. In this instance, the OWTS may be sized for
only one bedroom.
****For churches with food service, the 4 gal/meal must be added to the 3.5 gal/seat to
determine projected design flows.
Amend Sec. 30-6-20. Wastewater strength.
A. — No change.
B. High strength waste must be reduced to at least Treatment Level TL1 quality or lower before
applying to a soil treatment area. Waste strength levels defined in Tables 30-6-3 and 30-6-4
must be used to determine compliance.
Amend Table 30-6-3
Treatment Levels
Treatment
Level
TL 1 2
BOD5 (mg/L) CBOD51 (mg/L) TSS (mg/L)
180
Total Nitrogen
(mg/L)
80 60-80
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(Shading indicates higher treatment levels)
1 Requirements for CBOD5 are only related to effluent samples from a higher level treatment
system.
2 Domestic septic tank effluent prior to soil treatment or higher level treatment has a wide range
of concentrations. These values are typical, but values used for design must account for site
specific information.
3 Total Nitrogen does not apply to Treatment Levels TL2 and TL3. Processes intended to reduce
total nitrogen are addressed in Treatment Levels TL2N and TL3N. Any total nitrogen reductions
that may be observed for TL2 and TL3 are as a result of the treatment process for BOD5 and TSS
reductions.
4 NSF/ANSI Standard 245 - Wastewater Treatment Systems - Nitrogen Reduction requires
reduction of 50 percent rather than an absolute value.
Add Table 30-6-4 High Strength Wastewater*
BOD5 (mg/L)
TSS (mg/L)
Fats, Oils, Grease (FOG)
(mg/L)
Septic Tank Influent
>300
>200
>50
Septic Tank Effluent
>180
>80
>25
*High strength effluent prior to a septic tank has a wide range of concentrations. The values are typical, but
values used for design purposes must account for site -specific information.
ARTICLE VII - Minimum Distances Between Components of an On -Site Wastewater
Treatment System and Physical Features
Amend Sec. 30-7-20. Dry gulches, cut banks and fill areas.
A. Separation distances to dry gulches, cut banks and fill areas in Table 30-7-1 must apply
unless the designer or design engineer determines, by observation of the exposed slope of
the dry gulch or cut bank or by soil profile test pit excavations, that a limiting layer is present
that will direct or allow the effluent from the soil treatment area to move laterally and surface.
In this instance, a greater distance may be required.
B. — No change.
C. The separation distance between a component and the crest of a dry gulch or cut bank will
be evaluated for potential erosion or slope instability if the components and the slope are too
close together. If there is potential for erosion or instability, the separation distance must be
increased until the risk is minimized.
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Amend Sec. 30-7-30. - On -site Wastewater Treatment System design consideration and
treatment requirements - separation distances from soil treatment area.
A. and B. — No change.
C. Item 4 in Table 30-7-2 addresses the required vertical separation distance between the
infiltrative surface of the soil treatment area and the limiting layer or the required depth of soil
comprising the soil treatment area.
Amend Table 30-7-1
Minimum Horizontal Distances in Feet Between Components of an On -Site Wastewater
Treatment System
Installed After November 15, 1973 and Water, Physical and Health Impact Features
Component
Septic Tank, Higher
Level Treatment Unit,
Dosing Tank, Vault or
Vault Privy
Building Sewer or
Effluent Lines
STA Trench, STA Bed,
Unlined Sand Filter,
Subsurface Dispersal
System
Structure
without
basement
crawlspace or
footing drains
Property
Lines,
Piped or
Lined
Irrigation
Ditch
upslope
curtain
drain
Subsurface
Drain,
Intermittent
Irrigation
Lateral,
Drywell,
Stormwater
Structure
Spring,
Well,
Suction
Line
Potable
Water
Supply
Cistern'
Potable
Water
Supply
Line2
502 , 102
100 252
20
10
502 56
Structure
w/basement
crawlspace or
footing drains
5
0
i Lined Sand Filter
Lined
Evapotranspiration
Field or Outside of
Berm of Lined
Wastewater Pond
Unlined Sand Filter in
Soil With a Percolation
Rate Slower than 60
Minutes per Inch,
Unlined or Partially
Lined
Evapotranspiration
System, Outside of
Berm of Unlined
Wastewater Pond, or
System Not Relying on
60
60
100
102
15
102
25 2
15
15
5
0
10
102
Lake,
Watercourse
Irrigation
Ditch,
Stream,
Wetland
Dry
Gulch,
Cut
Bank,
Fill
Area
(from
Crest)
10 50 10
102
502 102
10
10
15
15
10
25
10
50 3 25
25 10
10
10
10
25
25 10
25 15
Septic
Tank Higher level
treatment unit Dosing
Tank Vault or Privy
5
5
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30
STA for Treatment
Other than Aerosol
System Not Relying on
STA for Dispersal
1003 102 125
125
10
0
25 3
10 10
NOTE: The minimum distances shown above must be maintained between the OWTS
components and the features described. Where soil, geological or other conditions warrant,
greater distances may be required by the Board of Public Health or by the Water Quality
Control Commission pursuant to Section 25-8-206, C.R.S., and applicable regulations. For
repair or upgrading of existing OWTS where the size of lot precludes adherence to these
distances, a repaired OWTS shall not be closer to setback features than the existing OWTS,
as reviewed and approved by the Water Quality Control Division. Components that are not
watertight should not extend into areas of the root system of nearby trees.
1 Includes potable wells, irrigation wells and monitoring wells set within a potable aquifer
and infiltration galleries permitted as wells by the Division of Water Resources.
2 Crossings or encroachments may be permitted at the points as noted above, provided
that the water or wastewater conveyance pipe is encased for the minimum setback distance
on each side of the crossing. A length of pipe with a minimum Schedule 40 rating of sufficient
diameter to easily slide over and completely encase the conveyance must be used. Rigid end
caps of at least Schedule 40 rating must be glued or secured in a watertight fashion to the
ends of the encasement pipe. A hole of sufficient size to accommodate the pipe must be
drilled in the lowest section of the rigid cap so that the conveyance pipe rests on the bottom
of the encasement pipe. The area in which the pipe passes through the end caps must be
sealed with an approved underground sealant compatible with the piping used. Other
methods of encasement that provide equal protection are allowed. These methods must be
designed by a professional engineer and approved by the local public health agency.
Add 8 feet additional distance for each 100 gallons per day of design flows between 1,000
and 2,000 gallons per day, unless it can be demonstrated by a professional engineer or
geologist by a hydrologic analysis or the use of a barrier, consisting of a minimum 30 mil PVC
liner or equivalent, that contamination will be minimized.
4
5
All horizontal setbacks to a potable water supply cistern must be met unless a variance
by the Board of Examiners of Water Well Construction and Plumb Installation Contractors
is granted per section 11.4 of the Water Well Construction Rules, 2 CCR 402-2. The
minimum horizontal setback that may be granted through a variance is to 25 feet.
If the structure is not used as a habitable unit, the isolation may be reduced by the local
board of health to no less than 50 feet.
6 Building sewer installations shall meet the design requirements of the Colorado Plumbing
Code.
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Amend Table 30-7-2
On -site Wastewater Treatment System Design Consideration and Treatment
Requirements - Separation Distances from Soil Treatment Area
Item
2
Distance from soil treatment area to on -site well
OWTS Design Consideration All Treatment Levels
Horizontal Separation Distances
Greater than or equal to
100 feet
Distance from soil treatment area to pond, creek, lake or Greater than or equal to
other surface water feature
3 Distance from soil treatment area to dry gulch or cut bank
Vertical Separation Distances
50 feet
Greater than or equal to
25 feet
Treatment depth in feet from infiltrative surface to a limiting 4 feet (3 feet with pressure
layer dosing)
NOTE: Treatment levels are defined in Table 30-6-3.
ARTICLE VIII - Design Criteria - General
Amend Sec. 30-8-10. Performance.
A. The OWTS for single-family homes shall be designed to accommodate the proposed flows
from the structure as defined in 30-6-10.B. Flow estimates for multi -family or commercial
OWTS must comply with 30-6-10.D.1. Expected waste strength as noted in Table 30-6-3 and
Table 30-6-4 must also be addressed, where applicable. Installation of low flow fixtures or the
separation of toilet waste or other sources of wastewater does not allow for the reduction in
the size of an OWTS.
B. OWTS shall be designed and constructed to achieve the treatment level specified by the
design.
Amend Sec. 30-8-20. Reliability.
OWTS must be designed and constructed such that each component shall function, when
installed and operated, in a manner not adversely affected by normal operating conditions,
including erosion, corrosion, vibration, shock, climatic conditions and usual household chemicals.
Each component must be free of nonfunctional protrusions or sharp edges or other hazards,
which could cause injury to persons, animals or properties. Design must be such as to exclude
flies and rodents and other vectors and to prevent the creation of nuisances and public health
hazards and must provide for efficient operation and maintenance.
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Amend Sec. 30-8-30. Accessibility for inspection, maintenance and servicing.
A. Septic tanks must have watertight risers over each access manhole, and all risers must extend
to or above final grade.
B. For new construction, the top of any septic tank, dosing tank or vault must be no deeper than
four feet below finished grade.
C. Each treatment component of an OWTS, other than the septic tank and soil treatment area,
shall be equipped with access manholes with risers that extend to or above final grade, located
to permit periodic physical inspection, collection and testing of samples and maintenance of
all components and compartments.
D. Riser lids.
1. Each riser lid must be watertight, brought to or above the surface, and must have a secure
closing mechanism, such as a lock, special -headed bolts or screws, or sufficient weight
(defined as 59 pounds) to prevent unauthorized access.
E. Components that require access for maintenance must include, but not be limited to,
submerged bearings, moving parts, pumps, siphons, valves, tubes, intakes, slots, distribution
boxes, drop boxes, cleanouts, effluent screens, filters, inlet and outlet baffles, aerators,
treatment equipment and other devices.
F. Components must be designed and constructed so that, when installed, they must be easily
maintained, sampled and serviced according to the manufacturer's recommendations. Easy
physical access to treatment components by maintenance personnel and equipment must
be provided.
Amend Sec. 30-8-40. Plumbing codes.
Plumbing fixtures, building sewers, vents, sewer lines and other appurtenances must be
designed, operated and maintained so as to comply with the minimum requirements of the locally
enforced plumbing code. In the absence of a local plumbing code, designs must adhere to the
Colorado Plumbing Code (3 CCR 720-1). A local plumbing permit may be required.
Amend Sec. 30-8-50. Electrical equipment.
A. All electrical work, equipment and materials must comply with the requirements of the locally
enforced code. A local electrical permit may be required.
B. Electrical components must be protected from moisture and corrosive gases.
Amend Sec. 30-8-60. Indicators of failure or malfunctioning for systems utilizing
mechanical apparatus.
A signal device must be installed which will provide a recognizable indication or warning to
the user that the system or component is not operating as intended. This indication or warning
must be a visual signal and audible signal, and must be located in a centralized area within visual
and audible range of the system user. A signal or message may also be sent remotely to a
maintenance provider.
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Amend Sec. 30-8-70. Sampling access.
A. If sampling for testing or as a requirement for a permit will be required of effluent from a
component other than the soil treatment area, an accessible sampling point must be
provided.
B. If sampling of the treated wastewater from the soil treatment area will be required for testing
or as a requirement for a permit, a monitoring well or wells must be constructed. Monitoring
wells must be located down gradient from the soil treatment area, accessible and provided
with a properly securable cover at or above the ground surface. Monitoring wells up gradient
of the system may also be required. Lysimeters or other collection devices under the soil
treatment area may be used instead of a monitoring well.
Amend Sec. 30-8-80. Component operating instructions.
A. The manufacturer of proprietary treatment units utilizing mechanical components must
provide clear, concise written instructions covering the components which, when followed,
must assure proper installation and safe and satisfactory operation and maintenance.
B. If the OWTS uses public domain technology, the design engineer must provide clear, concise
written instruction covering the components which, when followed, must assure proper
installation and safe and satisfactory operation and maintenance.
Amend Sec. 30-8-90. Surface activity.
Activity or use on the surface of the ground over any part of the OWTS must be restricted.
The soil treatment area must not be subject to damage or soil compaction from livestock, vehicular
traffic, recreational use, or other site development activity. Construction equipment not necessary
to install the OWTS must be kept off of the soil treatment area to prevent undesirable compaction
of the soils. If compaction occurs, the disturbed or compacted soil must be reevaluated and/or
new soil evaluations performed. The system must be redesigned if the soil permeability has
changed.
Amend Sec. 30-8-100. Floodplains.
A. A new, expanded or repair/replacement OWTS installed in a 100 -year floodplain must meet
or exceed the requirements of the Weld County Floodplain Management Ordinance
contained in Chapter 23 and the Federal Emergency Management Agency. Repairs of an
existing system must meet the requirements as feasible. The system, as approved by the
Division, must be designed to minimize or eliminate infiltration of floodwaters into the system
and discharge from the system into the floodwaters. The OWTS must be located to avoid
impairment to floodwaters or contamination from them during flooding. The Division has
available a floodplain guidance document.
B. A new or expanded OWTS must not be installed in a floodway designated in a 100 -year
floodplain where a conforming OWTS outside the floodway can be installed. For any new
OWTS or system repair that may affect the floodway delineation, appropriate procedures
must be followed, including revision of the floodway designation, if necessary.
Amend Sec. 30-8-110. Business, commercial, industrial, institutional or multi -family
dwelling wastewater systems.
A. An OWTS that will serve a business, commercial, industrial or institutional property or a
multi -family dwelling must:
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1. Be designed by a professional engineer;
2. Receive only such biodegradable wastes for treatment and distribution as are compatible
with those biological treatment processes as occur within the septic tank, any additional
treatment unit and the soil treatment area; and
3. Receive authorization by rule or a Class V underground injection permit from the United
States Environmental Protection Agency (EPA) before an application for an OWTS
permit is approved, if the system may receive nonresidential wastewater or is otherwise
covered by the EPA underground injection control program. Subsequent to acceptance
by the EPA, the Division may choose to also issue a permit for this type of use.
ARTICLE IX - Design Criteria - Components
Amend Sec. 30-9-10. Tanks and vaults.
A. Watertightness.
1. Septic tanks, vaults, dosing tanks, other treatment components, risers and lids must not
allow infiltration of groundwater or surface water and must not allow the release of
wastewater or liquids through other than designed openings.
2. When the final compartment of a tank is being proposed for use as a pump or siphon
chamber, the wall between this chamber and the previous chamber must be watertight
except for the intended hydraulic opening.
3. Acceptable watertightness testing methods, performed at a manufacturer's site or in the
field, include water filling the tank or vacuum testing.
B. Tank anchoring. In locations where groundwater or floodwaters may cause instability
problems to the septic tank, vault or other treatment unit in the OWTS due to flotation, the
tank, vault or unit must be anchored in a manner sufficient to provide stability when the tank
is empty. Risers must be included in the buoyancy calculations.
1. If a manufacturer provides recommendations for anchoring designs, they may be used
if they meet the conditions present at the site.
2. If a manufacturer does not provide recommendations for provisions to compensate for
buoyancy or if the professional engineer chooses to provide his or her own designs, the
anchoring system design must be prepared by the professional engineer.
C. Identification and data marking. All tanks and treatment units must be permanently and
legibly marked in a location, for the purpose of inspection, that is readily visible when
inspected before backfilling. The marking inscription must include the following:
1. thru 5. — No change.
Amend Sec. 30-9-20. Septic tanks.
A. The manufacturer must provide sufficient information to demonstrate that the tank will meet
the design specification.
B. Sizing requirements:
1. Sizing for residential capacity for new installations must be based upon the number of
bedrooms according to Table 30-9-1:
Table 30-9-1 — No change.
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2. For multi -family and nonresidential applications, a septic tank must be sized to permit
detention of incoming wastewater design flows for a minimum of forty-eight (48) hours.
3. and 4. — No change.
C. Inspection and Testing of septic tank watertightness.
1. Testing of septic tanks must be performed and evaluated as specified in Section 9 of
ASTM C1227-13 (Standard Specification for Precast Septic Tanks) for concrete tanks or
in Standard IAPMO/ANSI Z1000-2013 (American Standards for Prefabricated Septic
Tanks) for other prefabricated septic tanks.
2. Each unit must be inspected in the field for conditions that may compromise its
watertightness.
3. The inspection in the field must be conducted by the Division and be performed after the
tank installation but before backfilling.
4. — No change.
D. Septic tank design and dimension criteria.
1. A septic tank must have two (2) or more compartments or more than one (1) tank may
be used in a series. The first compartment of a two -compartment tank or the first tank in
a series must hold no less than one-half (1/2) of the required effective volume.
2. Inlet invert must be at least two (2) inches higher than the outlet invert.
3. Inlet tee or baffle must extend above the surface of the liquid at least five (5) inches and
must extend a minimum of eight (8) inches below the liquid surface. However, the inlet
tee or baffle must not extend to a depth of more than 40 percent of the liquid depth
measured from the liquid surface.
4. Outlet tee or baffle must extend at least five (5) inches above and fourteen (14) inches
below the outlet invert, however, it must not extend to more than 40 percent of the liquid
depth measured from the liquid surface. The outlet tee or baffle that accommodates an
effluent screen must be located so that the effluent screen has sufficient clearance to be
removed through the access opening with a riser in place.
5. The distance from the outlet invert to the underside of the tank top must be at least ten
(10) inches.
6. Liquid depth must be a minimum of thirty (30) inches and the maximum depth must not
exceed the tank length.
7. The transfer of liquid from the first compartment to the second or successive
compartment must be made at a liquid depth of between thirty-five percent (35%) and
forty-five percent (45%) of the liquid depth measured from the liquid surface.
8. At least one (1) access opening no less than twenty (20) inches across must be provided
in each compartment of a septic tank.
9. A septic tank must have a minimum of twenty-five (25) square feet of liquid surface area
and have at least a six-foot separation between inlets and outlets. Septic tanks in series,
combined, must have a minimum of twenty-five (25) square feet of liquid surface area
and the sum of the distances between inlets and outlets of all tanks must be at least six
(6) feet. The requirements for liquid surface area and separation between inlet and outlet
may be waived for tanks with less than seven -hundred -fifty -gallon effective volume.
E. Concrete septic tank structural design.
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1. Concrete septic tanks must comply with the structural design criteria of ASTM C1227-
13 (Standard Specification for Precast Septic Tanks).
2. and 3. — No change.
4. Tank slab lids, mid -seam tanks, and the connections between the tank and risers must
be designed to provide for a watertight seal.
F. Fiberglass, fiberglass -reinforced polyester and plastic tanks.
1. All fiberglass, fiberglass -reinforced polyester and plastic tanks must meet the minimum
design and structural criteria of IAPMO/ANSI Z1000-2013 (American Standards for
Prefabricated Septic Tanks) and be certified by a professional engineer as meeting these
standards. The professional engineer certifying the criteria must be registered or
licensed in the United States but need not be registered in Colorado.
2. All tanks must be sold and delivered by the manufacturer or manufacturer's designated
representative, preferably completely assembled. On -site tank assembly will be allowed
on an as -needed basis.
3. Tanks must be structurally sound and support external forces, as specified in the
standard referenced above, when empty, and internal forces when full. Tanks must not
deform or creep, resulting in deflection of more than five percent (5%) in shape as a
result of loads imposed.
4. All tanks must be constructed of sound, durable materials and not be subject to
excessive corrosion, decay, frost damage or cracking.
5. All seams or connections, including to risers, must be sealed to be watertight.
G. Metal tanks are prohibited.
Amend Sec. 30-9-30. Abandonment of tank.
A. The contents of a tank shall be pumped by a County licensed systems cleaner and properly
disposed by methods specified in Section 30-4-120.B.3.
B. — No change.
C. If the tank will remain in place. (see Subsection A. above):
1. The bottom of the tank must be broken so that the tank neither floats nor fills with water;
2. — No change.
3. The remaining void must be filled with gravel, sand or compacted soil; and
Remainder of Section - No change.
Amend Sec. 30-9-40. Pipe standards and bedding requirements.
A. Pipe standards.
1. All wastewater pipes used in portions of an OWTS that are pressurized must be
constructed of compatible pipe, primer, bonding agent and fittings. Flexible couplings to
connect pipes may only be used in portions of an OWTS that are intended for gravity
flow of the wastewater.
2. Where unperforated plastic pipe and fittings are used for gravity flow, the minimum wall
thickness of the pipe must conform to ASTM Standard D 3034 or equivalent or greater
strength. Schedule 40 pipe is preferred.
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3. Perforated distribution pipe surrounded by rock within a soil treatment area must have a
minimum wall thickness and perforations conforming to ASTM Standard D 2729 or
equivalent or greater strength. Corrugated polyethylene pipe with smooth interior that
meets ASTM F405 or AASHTO M252 specifications or equivalent may be used.
4. Schedule 40 or pipe of equivalent or greater strength must be used for the placement of
piping under driveways or roadways and in instances where sewer line setback
distances are granted a variance for any reason.
5. and 6. — No change.
B. Bedding. All system piping, except for distribution laterals within the soil treatment area, must
be bedded with select material before final inspection by the Division. Select bedding material
must consist of loose, granular material free from stones, clods, frozen soil or other
deleterious material. Select material may consist of on -site job -excavated or imported
material. Bedding material must be mechanically compacted to support piping.
Remainder of Section — No change.
Add Section 30-9-50. Cleanouts.
A. Cleanouts required between the building and the septic tank:
1. Cleanouts must have a secure cap and a riser extending to or easily accessible from
grade. The installation of a straight tee or sanitary tee is acceptable.
2. Cleanouts must be provided within five (5) feet of the outside of the building.
3. Where a sewer has a change of horizontal direction greater than 45 degrees, a cleanout
must be installed at the change of direction unless a cleanout already exists within 40 feet
upstream of this fitting. Where more than one change of direction greater than 45 degrees
occurs within 40 feet of a developed length of piping, the cleanout for the first change of
direction may serve as the cleanout for all changes within that 40 feet of developed length
of pipe.
4. Cleanouts must be provided at intervals within the building sewer from the structure to the
tank of not more than 100 feet. The effluent pipe between the septic tank and soil treatment
area is exempt from this requirement.
Amend Sec. 30-9-60. Distribution box.
A. A distribution box, if used, must be of sufficient size to distribute effluent equally to the laterals
of a trench or absorption bed system. The box must be constructed with the inlet invert at
least one (1) inch above the level of the outlet inverts. Flow equalizers or similar devices must
be used to adjust the flow between laterals. Access to the box must be provided with a
manhole riser with access lid at or above grade if the top of the box does not reach final grade.
1. Each lateral shall be connected separately to the distribution box.
2. The distribution box shall be watertight and all pipes shall be grouted or cemented. The
box shall be located a minimum of five (5) feet from the septic tank.
3. The distribution box must be located outside of the absorption area. Solid wall pipe must
be installed from the distribution box until the beginning of the absorption area.
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4. In the event that treatment tank effluent is discharged to the distribution box by a pump,
a baffle shall be installed in the distribution box. The baffle shall be secured to the bottom
of the box, extending vertically to a point level with the crown of the inlet pipe and shall
be perpendicular to the inlet. In lieu of a baffle, the inlet pipe may have a ninety -degree
bend which diverts effluent downwards into the distribution box.
Amend Sec. 30-9-70. Drop box.
In sequential or serial distribution, a watertight box may be used to transfer the effluent to the
following trench when the effluent in a trench has received the designed level for overflow to the
next trench. A drop box shall have a riser at or above final grade if the top of the box does not
reach final grade. Outlet pipes in a sequential distribution must be designed and installed so that
they may be capped off for resting periods.
Amend Sec. 30-9-80. Stepdown/relief Pipe.
In sequential or serial distribution, an unperforated pipe may be used to transfer the effluent
to the following trench when the effluent in a trench has received the designed level for overflow
from that trench.
Amend Sec. 30-9-90. Wastewater pumping and dosing siphon systems.
A. Pumps.
1. Non -clog pump opening must have at least two-inch diameter solids handling capacity
where raw wastewater is pumped. A pump opening must not have more than three -
fourths -inch diameter solids handling capacity if previously settled effluent is pumped.
2. and 3. — No change.
B. Floats and switches.
1. — No change.
2. Floats must be mounted on a stem separate from the pump discharge piping to allow for
removal, adjustment and replacement of the float from grade without removing the pump.
3. — No change.
4. Dosing siphons for pressure dosing and higher level treatment systems must provide for
a means of determining the number of dosing events.
C. Location of pump or siphon.
1. A pump or a siphon may be, installed in a separate tank following the septic tank. The
tank must be of sufficient volume to allow pump or siphon cycling commensurate with
the design capacity.
2. The second compartment of a two -compartment septic tank may only be used as the
pump tank when the tank is specifically designed for this purpose and it can be
demonstrated, to the satisfaction of the Division, that the minimum forty -eight -hour
detention time will not be decreased. The pump must be screened or provided with an
approved filtering device to assure that only liquid effluent will be discharged. The transfer
of liquid from the first to the second compartment must be at an elevation that is between
the inlet and outlet invert elevations, and through a standard tee designed and located
as per the requirements of section 30-9-20.D.4. Siphons must not be installed in the
second compartment of a two compartment tank.
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3. The use of a three -compartment septic tank, sized to provide the required effective
volume in the first two compartments with the pump or siphon in the third compartment
is acceptable for tanks specifically designed for this purpose. The transfer of liquid from
the second to the third compartment must be at an elevation that is between the inlet and
outlet invert elevation, and through a standard tee designed and located as per the
requirements of section 30-9-20.D.4.
D. Pump or siphon discharge piping.
1. The discharge pipe from the pumping or siphon chamber must be protected from
freezing by burying the pipe below frost level or sloping the pipe to allow it to be self -
draining. Drainage must be provided through the bottom of the pump or through a weep
hole located in the discharge pipe prior to exiting the tank.
2. The pump discharge piping must have a quick disconnect that is accessible from grade
to allow for easy pump access and removal.
3. The pipe must be sized to maintain a velocity of two (2) or more feet per second.
4. Pressure pipes must be designed to prevent air or vacuum locking and allow self draining
of the pipes.
E. Access.
1. The pump or dosing system tank, chamber or compartment must have a minimum
twenty -four -inch diameter access riser, made of corrosion -resistant material, extending
to or above ground level. A smaller diameter riser may only be installed if it is accepted
by the Water Quality Control Division as an integral component of a specific product
during the product review process.
2. The access riser must have a watertight connection to the pump or dosing
chamber/compartment to prevent infiltration or exfiltration. All other intrusions to the riser
for electrical or other component access must also be watertight.
F. Splice box.
1. Splice boxes must be located outside the pump system access riser and be accessible
from the ground surface.
2. Wire splices are prohibited inside the tank, dosing chamber or riser. Wire splicing must
be completed with corrosion -resistant, watertight connectors.
G. Controls.
1. Control panels or other electrical boxes used to control the functions of an OWTS must
comply with the following, as appropriate:
a. The pump system must have an audible and visual alarm notification in the event an
excessively high water condition occurs.
b. The pump must be connected to a control breaker separate from the high water
alarm breaker and from any other control system circuits. An electrical disconnect
must be provided within the line of sight of the pump chamber.
c. The pump system must be provided with a means that will allow the pump to be
manually operated.
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d. The pump system for pressure dosing and higher level treatment systems must have
a mechanism for tracking both the amount of time the pump runs and the number of
cycles the pump operates.
e. Must bear the seal of a Nationally Recognized Testing Laboratory (NRTL), such as
UL or ETL.
Amend Sec. 30-9-100. Effluent screens.
A. If a pump or dosing siphon is used to remove septic tank effluent from the final compartment
of the septic tank, the effluent must be filtered prior to dispersal into the soil treatment area.
An effluent screen, pump vault equipped with a filter cartridge, or a filter on the discharge
pipe, would all be considered acceptable.
B. The effluent screen, if used, must be cleaned at manufacturer -recommended intervals or
more often, if use patterns indicate.
C. An alarm may be installed on an effluent screen indicating need for maintenance.
D. Where an ejector pump, grinder pump or non -clog pump is proposed for use prior to the
septic tank, an effluent screen must be installed on the outlet of the septic tank.
E. The handle of the effluent screen must extend to within 12 inches of grade.
Amend Sec. 30-9-110. Grease interceptor tanks.
A. and B. — No change.
C. The grease interceptor must have a minimum of two compartments and must be sized
proportionate to the amount of fats, oils and grease it receives, the peak flow rate through
the tank, and the expected cleaning frequency.
D. The inlet and outlet tees or baffles must extend into the bottom 1/3 of the liquid volume, but
must be at least 12 inches off the inside floor of the interceptor.
E. The inlet and outlet tees or baffles must extend at least 5 inches above the liquid level and
must provide for a free vent area across the liquid surface.
ARTICLE X - Design Criteria - Soil Treatment Area
Amend Sec. 30-10-10. — Soil Treatment Area General.
A. The size and design of the soil treatment area must be based on the results of the site and
soil evaluation, design criteria and construction standards for the proposed site and OWTS
selected.
B. At proposed soil treatment area locations where any of the following conditions are present,
the system must be designed by a professional engineer and approved by the Division:
1. For soil types, 3A, 4, 4A, 5, R-0, R-1 and R-2, as specified in Table 30-10-1 and 30-10-
1A of this Regulation;
2. The maximum seasonal level of the groundwater surface is less than four (4) feet below
the bottom of the proposed infiltrative surface;
3. A limiting layer exists less than four (4) feet below the bottom of the proposed infiltrative
surface;
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4. The ground slope is in excess of thirty percent (30%); or
5. Pressure distribution is used.
Amend Sec. 30-10-20. Calculation of infiltrative surface of soil treatment area.
A. — No change.
B. Long-term acceptance rates (LTARs) are shown in Table 30-10-1 and 30-10-1A.
C. — No change.
D. The required area for a soil treatment area is determined by the following formula:
Soil treatment area in feet required = Design flow (in gallons per day)
LIAR (in gallons per day per square foot)
1. and 2. — No change.
3. Size adjustment factors for types of distribution media are in Table 30-10-3.
4. and 5. — No change.
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Amend Table 30-10-1
Soil Treatment Area Long -Term Acceptance Rates by Soil Texture, Soil Structure,
Percolation Rate and Treatment Level
3A
5
Soil Type, Texture, Structure and Percolation Rate Range
USDA Soil Texture
>35% Rock (>2mm):
See Table 30-10-1A
Sand, Loamy Sand
Sandy Loam, Loam,
Silt Loam
Sandy Clay Loam,
Clay Loam, Silty Clay
Loam
Sandy Clay Loam,
Clay Loam, Silty Clay
Loam
Sandy Clay, Clay,
Silty Clay
Sandy Clay, Clay,
Silty Clay
Soil Types 2-4A
USDA Soil
Structure - Type
>35% Rock
(>2mm): See Table
30-10-1A
Single Grain
PR (Prismatic) BK
(Blocky) GR
(Granular)
PR, BK, GR
Massive
la —USDA Soil Percolation Rate
Structure - Grade (MPI)
>35% Rock
(>2mm): See Table
30-10-1A
0 (Structureless)
2 (Moderate)
3 (Strong)
1 (Weak)
0 (Structureless)
16-25
0.60
PR,BK,GR 2,3
PR, BK, GR
Massive
PR, BK, GR
1
0 (Structureless)
2, 3
>35% Rock >35% Rock (>2mm): See Table
(>2mm): See Table
30-10-1A 30-10-1A
Long -Term Acceptance Rate
(L TAR); Gallons per day per
square foot
All Treatment Levels
5-15
26-40
41-60
61-75
PR,BK,GR 1
Massive 0 (Structureless)
Platy
1,2,3
76-90
0.80
0.50
0.35
0.30
0.20
91-120
121+
0.15
0.10
Shaded areas require system design by a professional engineer.
I Treatment levels are defined in Table 30-6-3.
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Add Table 30-10-1A Design Criteria for Soils with High Rock Content (Type "R" Soils) 1'2'3'4
I Soil Type, Percentage
of Rock, LTAR, Distribution
Required Sand or
Media Depth Relative
to the Quality of
Effluent Applied to the
Distribution System
Soil Type
Percentage and
Size of Rocks
Maximum LTAR
(gal/sq ft/day
Type of Distribtion
Required
__....._.
Treatment Level 16
R-0
Soil Type7 1 with
more than 35%
Rock (>2mm)
Unlined Sand Filter:
1.0 for "Preferred
Sand Media:, 0.8 for
"Secondary Sand
Media"
Pressure
Distsributions
Minimum 3 -foot
deep Unlined Sand
Filter
R-1; Option 1
Soil Type' 2-5,
>35%-65% Rock
(>2mm); With >50%
of the Rock <20 mm
(3/4 inch)
Use TL1 LTAR from
Table 30-10-1 for the
soil type
corresponding to the
soil matrix with a
maximum LTAR of
0.8
Pressure
Distributions
Minimum 2 -foot
deep Unlined Sand
Filter
R-1; Option 2
Soil Type7 2 and 2A,
>35%-65% Rock
(>2mm); With >50%
of the Rock <20 mm
(3/4 inch)
The allowable LTAR's
are defined in each
individual treatment
level column in this
table
Pressure
Distributions
Remove, mix,
replace 4 feet of
existing material;
with a maximum
LTAR
R-2
Soil Type' 2-5,
>65% Rock (>2mm),
OR >50% of Rock
>20mm (3/4 inch)
Use TL1 LTAR from
Table 30-10-1 for the
soil type
corresponding to the
soil matrix, with a
maximum LTAR of
0.8
Timed,
Pressure
Distributions
Minimum 3 -foot
deep Unlined Sand
Filter
1. General guidance for Table 30-10-1A: The intent of the soil type R-0 is to define a material that consists of a
high percentage of rock, or rock fragments, and has a percolation rate of less than 5 mpi. Soil types R-1 and
R-2 consist of a high percentage of rock or rock fragments, but have a percolation rate of greater than 5 mpi.
Soil types R-0 and R-2 are considered to be a "limiting layer".
2. No sizing adjustments are allowed for systems placed in type "R" soils. The maximum LTAR's are provided
in this table
3. The design of type "R" soil treatment systems must conform to sections 30-11-30.B and C.
4. All systems installed in a type "R" soil must be designed by a professional engineer.
5. The percentage of rock may be determined by a gradation conducted per ASTM standards, or an
appropriate field evaluation by volume.
6. Type "R" soil treatment systems that are designed per the criteria noted in the Treatment Level 1 column of
this table do not require O/M oversight by the LPHA.
7. The "Percentage and Size of Rock" column references the soil types noted in Table 30-10-1.
8. Design of the pressure distribution system for type "R" soils shall comply with the requirements of sections 30-
11-30 B. 2. a, b, c, d, and e.
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Amend Sec. 30-10-30. Allowable soil treatment area Sizing Adjustments.
A. The soil treatment area size, determined by dividing the design flow rate by the long-term
acceptance rate, may be adjusted by factors for soil treatment area design and type of
distribution media.
B. For the purpose of the table, a "baseline system," i.e., adjustment factor of 1.00, is
considered to be Treatment Level 1 (TL1) applied by gravity to a gravel -filled trench.
Delete C.
Table 30-10-2 — No change.
Amend Table 30-10-3
Size Adjustment Factors for Types of
Distribution Media in Soil Treatment Areas
Type of Storage/Distribution Media
Used in Soil Treatment Area
Type of Soil Treatment Area
l
Trench or bed
Category 1
Rock or Tire Chips
Category 2
Category 3
Other Manufactured Media
Chambers or
Enhanced
Manufactured
Media
1.0 0.9
0.7
1. All proprietary distribution products must receive acceptance and the applicable reduction through
Colorado Water Quality Control Division review per the applicable requirements of Regulation 43
section 43.13.
Amend Sec. 30-10-40. Design of distribution systems.
A. General.
1. The infiltrative surface and distribution laterals must be level.
2. The infiltrative surface must be no deeper than four (4) feet below grade. The depth of the
infiltrative surface will be measured on the up -slope side of the trench or bed.
3. thru 6. — No change.
7. Backfilling and compaction of soil treatment areas must be accomplished in a manner that
does not impair the intended function and performance of the storage/distribution media
and soil and distribution laterals, allows for the establishment of vegetative cover,
minimizes settlement and maintains proper drainage.
8. Dosing may be used for soil treatment area distribution. The dose must be sized to account
for the daily flow and the dosing frequency.
B. Distribution Laterals; Must meet the requirements of Section 30-90-40, as applicable.
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1. Distribution between laterals in a soil treatment area must be as level as possible. Uneven
settling of portions of the distribution system following construction must be addressed by
provisions in the design to adjust flows between laterals.
2. The maximum length of distribution laterals must not exceed one hundred fifty (150) feet.
3. Distribution laterals longer than one hundred (100) feet must be pressure dosed or the
application of the effluent must be at the center of the lateral through a distribution box.
4. For absorption beds, the separating distance between parallel gravity distribution laterals
must not exceed six feet (center -to -center), and a distribution lateral must be located within
three feet of each sidewall and endwall.
5. The end of a distribution pipe must be capped unless it is in a bed or trenches in a level
soil treatment area, where the ends of the lines may be looped.
6. To promote equal distribution to the soil treatment area, the forcemain or effluent pipe
must be connected to as near to the middle of the distribution header as possible.
However, it must be offset from any distribution lateral to prevent preferential flow.
7. Orifices must be oriented downward unless pressure distribution is used and provision for
pipe drainage is included.
C. Pressure Distribution.
1. Design of pressure distribution systems must include:
a. Dose size and frequency for either proposed flows and soil type, or media long-term
acceptance rate;
b. Pipe diameter and strength requirements;
c. Orifice size and spacing;
d. A 30 — 72 inch operating head at the distal end orifice;
e. Pump/siphon information; Total Dynamic Head; gallons/minute;
f. Drain -back volume from forcemain; and
g. Calculations, or a design software reference, that indicates the selected component
sizing will provide equal flow within each active zone of the distribution system, and
provide no more than a 10% flow differential from the initial orifice to the most distal
end orifice within each zone.
2. The separating distance between parallel distribution pipes in a pressure distribution
absorption bed must not exceed four feet, and the outer distribution pipe must be located
within two feet of each sidewall and endwall. Specific requirements for the design of sand
filters are noted in section 30-11-30.B.
3. Flushing assemblies must be installed at the distal end of each lateral and be accessible
from finished grade. A sweeping 90 degree or bends limited to 45 degree must be
provided.
Delete 5. Inspection ports.
Add and Amend Sec, 30-10-50, Soil Treatment Area Requirements
A. Trenches.
1. Trenches must be three (3) feet wide or less.
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2. The separating distance between trenches must be a minimum of four (4) feet, sidewall-
to-sidewall.
3. Distribution laterals used in a trench must be as close to the center of the trench as
possible.
B. Beds.
1. Maximum width for a bed shall be twelve (12) feet, unless the bed receives effluent
meeting Treatment Level 2 quality or better.
2. The separation distance between beds must be a minimum of six (6) feet, sidewall to
sidewall.
C. Serial and sequential distribution.
1 A serial or sequential distribution system may be used where the ground slope does not
allow for suitable installation of a single level soil treatment area, unless a distribution box
or dosing chamber is used.
2. The horizontal distance from the side of the absorption system to the surface of the
ground on a slope must be adequate to prevent lateral flow and surfacing.
3. Adjacent trenches or beds must be connected with a stepdown/relief line or a drop box
arrangement such that each trench fills with effluent to the top of the gravel or chamber
outlet before flowing to succeeding treatment areas.
D. Alternating systems.
1. An alternating system must have two (2) or more zones that must be alternated on an
annual or more frequent basis.
2. For repairs, each section must be a minimum of fifty percent (50%) of the total required
soil treatment area. For new installations, each separate soil treatment area must meet
the minimum sizing requirements of this regulation.
3. A diversion valve or other approved diversion mechanism that requires the owner or
operator to manually alternate zones of the OWTS may be installed on the septic tank
effluent line allowing soil treatment area sections to be alternated.
4. The diversion mechanism must be readily accessible from the finished grade.
E. Sequencing zone systems.
1. Sequencing zone systems have two (2) or more soil treatment area sections that are
dosed on a frequent rotating basis.
2. Where soil conditions are similar between the sections, each section area must be the
same size. If soil conditions are such that long-term acceptance rates are different, each
section may be sized for the same dose, but different long-term acceptance rates.
3. and 4. — No change.
F. Inspection Ports.
1. A 4 -inch inspection port accessible from ground surface must be installed at the terminal
end of each lateral in a trench system and at each corner of a bed system. The bottom
of the inspection port tube must extend to the infiltrative surface and not be connected to
the end of the distribution pipe.
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2. Inspection ports in chambers may be installed according to manufacturer's instructions if
the infiltrative surface is visible and effluent levels can be observed from the inspection
port.
3. Additional inspection ports connected to distribution pipes may be installed.
4. The top of the inspection ports may be terminated below the final grade if each is housed
in a component such as a valve box for a lawn irrigation system and has a removable
cover at the ground surface.
Amend Sec. 30-10-60. Storage/Distribution Media
A. Rock and Pipe.
1. The perforated pipe must be surrounded by clean, graded gravel, rock, or other material
of equal efficiency which may range in size from 1/2 inch to 2 1/2 inches. AASHTO M 43
size No. 3 coarse aggregate meets this specification.
2. At least six inches of gravel, rock or other material must be placed below the pipe. The
gravel, rock or other material must fill around the pipe and be at least two inches above
the top of the distribution pipe.
3. The top of the placed gravel or such material used must be covered with non -woven
permeable geotextile meeting a maximum thickness rating of 2.0 ounces per square yard
or equivalent pervious material. An impervious covering must not be used.
B. Chambers.
1. Chambers must be installed with the base of the unit on in -situ soil or, if placed on
acceptable media, the manufacturer's installation instructions must be followed so as to
prevent chambers from settling into the media.
2. Installation must be according to manufacturer's instructions.
3. Effluent may be distributed by gravity, pump or siphon.
4. If the width of a proprietary manufactured distribution product is within 90 percent of the
width of the excavation, it may be approved as being equivalent to the full width of the
excavation, if information is provided that demonstrates distribution of the full width. Thus,
the product must cover at least 90 percent of the excavated area in either a trench or bed
configuration in order to receive sizing adjustments provided in Table 30-10-3.
C. Media, Enhanced, or Other Manufactured
1. Manufactured media must be installed with the base on the in -situ soil or placed on
acceptable media meeting the manufacturer's specifications for proprietary distribution
products or combined treatment/distribution products.
2. Installation must be according to manufacturer's instructions.
3. Pressure distribution is required for TL2-TL3N effluent, unless otherwise noted in this
regulation.
D. Driplines.
1. The infiltrative surface area must be calculated using the long-term acceptance rate for
the site or a more conservative value if recommended by the manufacturer.
2. Driplines must be installed on manufacturer's spacing recommendations.
3. Drainback must be provided for all driplines, pipes and pumps.
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4. Provisions must be made to minimize freezing in the distribution pipes, driplines, relief
valves, and control systems.
5. Provisions must be made for filtering, back -flushing, or other cleaning.
E. Tire Chips.
1. The pipe may be surrounded with clean, uniformly -sized tire chips.
2. Tire chips must be nominally two inches in size and may range from 1/2 inch to a maximum
of four inches in any one direction.
3. Wire strands must not protrude from the tire chips more than 0.75 inches.
4. Tire chips must be free from balls of wire and fine particles less than two mm across.
5. The top of the tire chips used must be covered with non -woven permeable geotextile
meeting a maximum thickness rating of 2.0 ounces per square yard or equivalent pervious
material. An impervious covering must not be used.
Amend Sec. 30-10-70. Lift stations.
Lift stations intended solely for the purpose of delivering sewage to a septic tank, or septic
tank effluent to a standard soil treatment area that is located such that it is not possible to provide
gravity flow from the septic tank to the soil treatment area, are not required to be designed by a
professional engineer. The systems installer shall submit to the Division a pump information form,
provided by the Division, for documentation.
Amend Sec. 30-10-80. Soil replacement.
A. The construction of a soil replacement system is permitted to bring the soil treatment area
into compliance with the requirements of this regulation.
1. When a soil type "R" is removed, the following requirements must be met:
a. All added soil must comply with the following specifications:
1) Added soil must meet the specifications of either "preferred" or "secondary" sand
filter media, as specified in section 30-11-30 B.4.
2) The long-term applicable rates as specified in Table 30-10-1A must be used. No
additional sizing adjustments are allowed.
3) The depth of the added media must comply with the requirements of Table 30-10-
1A.
4) A gradation of the sand media used must be provided. The gradation must be
dated no more than one month prior to the installation date. However, a gradation
of the actual material placed in the excavation is recommended.
5) All added soil must be completely settled prior to installation of components as
specified and approved by the design engineer.
6) Pressure distribution must be used.
2. The removal and reinstallation of in -situ soil may only be allowed where the soils are
determined to be a soil type "R-1" (Option 2). The design must comply with the
requirements for this soil type noted in Table 30-10-1A (Soil Type R-1, Option 2).
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3. When a sand media is added to soil treatment area or to an excavation where a soil type
1-5 (Table 30-10-1) is the underlying soil, the following requirements must be met:
a. Added soil must meet the specifications of either "preferred" or "secondary" sand filter
media, as specified in section 30-11-30 B.4.
b. Unless the design follows the criteria for a sand filter or mound system design as
required in section 30-11-30, the TL1 long-term acceptance rate for the receiving soil
must be used.
c. A gradation of the sand media used must be provided. The gradation must be dated
no more than one month prior to the installation date. However, a gradation of the
actual material placed in the excavation is recommended.
d. All added soil must be completely settled prior to installation of components.
Amend Sec. 30-10-90. Repairs.
A. When space is not available or if there are other site limitations that preclude other soil
treatment area options for OWTS repairs, wide beds, deep beds and deep gravel trenches
may be considered for repairs only. Other options are vaults (in accordance with Section 30-
12-40 of this Chapter) or higher level treatment systems.
B. Repairs to failing systems must conform to setbacks identified in Table 30-7-1 when possible.
When this is not possible using all available methods described above, the jurisdiction with
authority may permit reductions to setbacks. At no point will a setback reduction be approved
by the jurisdiction less than what the existing separation is to existing OWTS. In maximizing
this setback distance, all methods available in section 30-10-90 A. must be utilized including
but not limited to the use of Higher Level Treatment, wide beds, etc., where allowed. Any
setback reduction beyond what the existing failing system presents must be approved by the
local board of health as outlined in section 30-4-140.
C. Wide beds. For repairs, beds may be wider than twelve (12) feet without being required to
receive effluent meeting Treatment Level 2 quality or better.
D. Deep Beds: For repairs, the infiltrative surface of a bed may be no deeper than five feet. Size
adjustments as provided for in Tables 30-10-2 and 30-10-3 must not be applied. System sizing
will be based strictly on the soil type and corresponding LTAR.
E. Deep gravel trenches.
1. The length of an absorption trench may be calculated by allowance for the sidewall area
of additional depth of gravel in excess of six (6) inches below the bottom of the
distribution pipe, according to the following formula:
Adjusted length = L x (W+2)
(W+1+2D)
Where:
L = Length of trench prior to adjustment for deep gravel
W = Width of trench in feet
D = Additional depth in feet of gravel in excess of the minimum required 6 inches of
gravel below the distribution pipe
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2. Maximum allowable additional depth is five (5) feet.
3. Percolation tests or soil profile test pit excavations must be performed at the proposed
infiltrative surface depth.
4. Size adjustments as provided for in Table 30-10-2 and 30-10-3 must not be applied to
deep gravel trenches.
F. Wastewater Ponds.
1. Construction of new wastewater ponds is prohibited.
2. For repairs of an existing wastewater pond, the potential for risk to public health and water
quality may be evaluated by the local public health agency. If risk is low in the
determination of the local public health agency, the repair of a wastewater pond may be
permitted, however the following criteria must be followed:
a. A septic tank must precede the wastewater pond.
b. The depth of the design volume of the wastewater pond must be at least five feet.
c. A wastewater pond must have two feet of free board above the design volume of the
pond.
d. A wastewater pond must be fenced to keep out livestock, pets, vermin, and
unauthorized people.
e. Wastewater ponds must be designed on the basis of monthly water balance including
design flow, precipitation, evaporation, and seepage.
f. Wastewater ponds must be constructed so the seepage out of the bottom or sides
does not exceed 1/32 of an inch per day. If this limit cannot be achieved using
compacted natural soil materials including soil additives, an impermeable synthetic
membrane liner must be used.
g.
If the evapotranspiration does not exceed the rate of inflow of effluent from the
structure, a soil treatment area meeting the requirements of this regulation must be
installed to accept the excess flow.
h. Maintenance must include preventing aquatic and wetland plants from growing in or
on the edge of the pond, protecting sides from erosion, and mowing grasses on the
berm and around the pond.
i. Wastewater ponds must be designed by a professional engineer.
G. Vaults. The allowable use of vaults for repairs must meet the criteria specified in Section 30-
12-20 of this Chapter.
H. Higher level treatment options.
1. Design criteria for higher level treatment systems are in Article XI below.
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ARTICLE XI - Design Criteria - Higher Level Treatment Systems
Amend Sec. 30-11-20. Treatment levels.
The treatment levels identified in Table 30-6-3 are specified in this Section for public domain
technology, and proprietary systems will be assigned to a treatment level approved by the Water
Quality Control Division. Adequate maintenance and operation plan as required by the Water
Quality Control Division must be submitted to the Division.
Amend Sec. 30-11-30. Sand filters.
A. A lined or unlined intermittent sand filter or recirculating sand filter, may be used as a higher
level -treatment system prior to dispersing the effluent into a soil treatment area.
B. Intermittent (single -pass) sand filters; General Requirements.
1. The treatment level for intermittent sand filters is considered TL3.
2. General Design Parameters: Not all combinations of the variables noted below will result
in a proper distribution system design. The design engineer must justify through
calculations or design software that the selected values will concur with industry
standards.
a. Distribution pipe size: 3/4 inch — 1.5 inches (PVC Class 200, min.)
(1) 2 inch distribution pipe may only be used where other design modifications cannot
overcome a greater than 10% variation in the pressure head between the initial
and distal orifices.
(2) Distribution pipe spacing: 18 inches — 48 inches
(3) Orifice size: 1/8 inches — 3/8 inches (Also see section 30-11-30 E.1. below)
(4) Orifice spacing: 18 inches — 48 inches
(5) Operating head at the distal end of distribution pipes: 30 inches — 72 inches (60
inches typ.). Larger orifices allow for an operating head at the lower end of this
range, while smaller orifices will necessitate an operating head at the higher end
of this range.
3. Dosing:
a. Pressure distribution is required. The design of the distribution system must also
comply with the requirements of 30-10-40 C.1.
b. Number of cycles/day: Will vary with design (Short, frequent doses are preferred.)
c. Proposed dose volume: Will vary with design (0.25 - 1.0) gallons/orifice/dose, or 3-5
times distribution pipe volume
d. Timed dosing is recommended where design considerations allow.
4. Sand Filter Treatment Media
a. The depth of the sand media below the distribution system must be at least 24 inches
unless otherwise noted in Table 30-10-1A for type "R" soils.
b. "Preferred" sand media requirements:
(1) Effective size: 0.25-0.60 mm
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(2) Uniformity coefficient: ≤ 4.0
(3) Percent fines passing #200 sieve: ≤ 3.0
c. "Secondary" sand media requirements:
(1) Effective size: 0.15-0.60 mm
(2) Uniformity coefficient: ≤7.0
(3) Percent fines passing #200 sieve: ≤ 3.0
d. A gradation of the sand media used must be provided. The gradation must be dated
no more than one month prior to the installation date. However, a gradation of the
actual material placed in the excavation is recommended.
5. Gravel Requirements
a. Clean, graded gravel, or rock, must range in size from 1/2 inch to 2 1/2 inches.
AASHTO M 43 size No.3 coarse aggregate meets this specification.
(1) The gravel must surround the distribution pipes used to disperse the effluent and
must be at least 6 inches below and 2 inches above the pipes.
(2) Water Quality Control Division accepted manufactured media may be used as an
alternative to specified gravel.
6. Filter Fabric Requirements
a. The top layer of gravel must be covered with a non -woven pefineable geotextile fabric
meeting a maximum thickness rating of 2.0 ounces per square yard or equivalent
pervious material.
7. Final Cover Material
a. 8 inches — 10 inches of Type 1 or 2 soil with an additional 2 inches top soil
8. Size adjustment factors provided in Tables 30-10-2 and 30-10-3 are not applicable for
sand filters.
9. Sand filters must not be used to treat wastewater that does not conform to TL1 treatment
level or better.
C. Unlined (open bottom) sand filters.
1. All requirements for 30-11-30 B. 1-9 will apply to unlined sand filters.
2. Application rates:
a. Maximum hydraulic loading rate for TL1 effluent applied to "Preferred Sand Media" in
an unlined sand filter is 1.0 gal./sq.ft./day, or the long-term acceptance rate of the
receiving soil for TL1 (Table 10-1) whichever results in the larger area.
b. Maximum hydraulic loading rate for TL1 effluent applied to "Secondary Sand Media"
in an unlined sand filter is 0.8 gal./sq.ft./day, or the long-term acceptance rate of the
receiving soil for TL1 (Table 10-1) whichever results in the larger area.
c. Maximum hydraulic loading rate for TL2, TL2N, TL3, or TL3N effluent applied to
"Preferred" or "Secondary" Sand Media in an unlined sand filter must be the long-
term acceptance rate of the receiving soil for TL1, (Table 10-1).
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3. The upper infiltrative surface of an unlined sand filter receiving TL1 — TL3N effluent must
be at least three (3) feet above a limiting layer.
D. Lined Sand Filters
1. All requirements of 30-11-30 B.1-9 will apply to unlined sand filters.
2. Application rates:
a. Hydraulic loading rate for TL1 effluent applied to "Preferred Sand Media" in a lined
sand filter is 1.0 gal./sq.ft./day.
b. Hydraulic loading rate for TL1 effluent applied to "Secondary Sand Media" in a lined
sand filter is 0.8 gal./sq.ft./day.
3. The minimum depth of the sand media in a lined sand filter must be two feet.
4. An intermediate layer of pea gravel, two inches in thickness, must be placed between the
sand filter media and the coarse under -drain media to prevent the migration of sand into
the lower layer of under -drain gravel. ASTM C 33, No. 8, coarse aggregate meets this
specification.
5. A minimum four -inch diameter slotted SCH40 PVC under -drain pipe must be used to
collect the treated effluent. The under -drain pipe must be installed in the center of a 5
inches thick bed of washed, graded gravel, or rock ranging in size from 1/2 inch to 2 1/2
inches. AASHTO M 43, No.3 coarse aggregate meets this specification. Lined sand filters
must have an impervious liner on the sides and bottom of the filter. The liner must consist
of a minimum 30 mil thick PVC material or equivalent.
6. Effluent collected by the under -drain must be dispersed to a soil treatment area. The soil
treatment area may be sized with a maximum long-term acceptance rate of the receiving
soil for TL1 effluent.
E. Recirculating Sand Filter, Minimum Requirements:
1. Treatment level:
a. Treatment level provided within recirculating sand filters is TL3.
1) General Design Parameters: Not all combinations of the variables noted below will
result in a proper distribution system design. Engineer must justify through
calculations or design software that the selected values will concur with industry
standards.
b. Distribution pipe size: 3/4 inch — 2 inches (PVC Class 200, min.)
c. Distribution pipe spacing: 18 inches — 36 inches (24 inches typ.)
d. Orifice size: 1/8 inch — 1/4 inch
e. Orifice spacing: 18 inches — 36 inches (24 inches typ.)
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f. Pressure head at end of distribution pipe: 24 inches — 72 inches (60 inches typ.)
2. Dosing:
a. Timed dosed, pressure distribution is required. The design of the distribution system
must comply with the requirements of section 30-10-40 C.1.
b. Recirculation ratio: 3:1 — 5:1
c. Gallons/orifice/dose: 1 — 3 (2.0 typ.)
d. Hydraulic loading: 3 - 5 gal./sq.ft./day (4 — 5 typ.)
e. Dosing time "ON"; <2.5 min. (<2.0 typ.)
f. Number of cycles/day: 48 — 120
3. Top gravel requirements:
a. Washed, graded gravel, or rock, must range in size from 1/2 inch to 2 1/2 inches.
AASHTO M 43, No.3 coarse aggregate meets this specification.
b. The gravel must surround the distribution pipes used to disperse the effluent and must
be at least 6 inches below and 2 inches above the pipes.
c. State accepted manufactured media may be used as an alternative to specified gravel.
d. Soil cover is prohibited. The upper gravel layer must be open to the atmosphere.
4. Filter media requirements:
a. Effective size: 1.5 — 2.5 mm
b. Uniformity coefficient: ≤ 3
c. Fines passing #200 sieve: ≤ 1.0
d. Media depth (min.): ≥24 inches
5. Intermediate gravel layer:
a. An intermediate layer of pea gravel, two inches in thickness, must be placed between
the coarse under -drain media and the sand filter media to prevent the migration of
sand into the lower layer of under -drain gravel (ASTM C 33, No. 8, coarse aggregate).
6. Under -drain requirements:
a. A minimum four -inch diameter slotted SCH40 PVC under -drain pipe must be used to
collect the treated effluent. The under -drain pipe must be installed in the center of a 5
inches thick bed of washed, graded gravel, or rock ranging in size from 1/2 inch to 2
1/2 inches. AASHTO M 43, No.3 coarse aggregate meets this specification.
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7. PVC liner requirements:
a. Lined sand filters must have an impervious liner on the sides and bottom of the filter.
The liner must consist of a 30 mil thickness PVC material or equivalent.
b. Effluent collected from the recirculating sand filter must be discharged to a soil
treatment area. The soil treatment area may be sized with a maximum long-term
acceptance rate of the receiving soil for TL1 effluent.
Add Sec. 30-11-40. Mound Systems.
A. When the infiltrative surface area of the media receiving wastewater effluent is at or above
the natural ground surface at any point, it shall be considered a mound system.
B. Mound systems that provide a minimum of 24 inches of sand treatment media may use the
application rates for the in -situ receiving soil for TL1 effluent (Table 10-1). Size adjustment
factors within Table 30-10-3 may be applied if TL1 application rates are used.
C. Mound systems must conform to the design requirements of sections 30-11-30 C.1-5 for
unlined (open bottom) sand filters, with the following exceptions.
1. A mound system may include less than 24 inches of imported sand media on a site where
a lesser depth of sand media is sufficient to meet vertical separation requirements above
a limiting layer. Application rates for the in -situ receiving soil for TL1 effluent must be used
when less than 24 inches of sand media is used, unless higher level treatment is provided
prior to dispersal into the mound system.
2. For the design of a mound system where less than 24 inches of sand media is proposed,
and application rates for TL1 are used, the size adjustment factors within Table 30-10-3
may be used.
D. The basal area must be determined using the LTAR from Table 30-10-1 for the in -situ
receiving soil under the mound.
E. Linear loading rates must be determined. The evaluation of many factors is required for an
accurate determination of the linear loading rate. While application rates for the in -situ
receiving soil under the mound is a main component, placement on the slope, and percent of
the slope must also be addressed when defining the linear loading rate. If the movement of
the effluent is primarily vertical, then the linear loading rate is not as critical. However, if the
movement of the effluent will be primarily horizontal, as would be expected in soil types 3A
through 5 (Table 30-10-1), then the linear loading rate is extremely important and long narrow
mounds are strongly recommended.
1. When TL1 effluent is applied to the distribution media of a mound system installed above
in -situ soil types 1 through 3 (Table 30-10-1) and R-0 through R-2 (Table 30-10-1A), the
suggested linear loading rate is between 6 gpd/lin.ft. and 12 gpd/lin.ft. The maximum width
of the distribution media in a mound system installed above these soil types is 12 feet
when TL1 effluent is applied to the distribution media of a mound system.
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2. When TL2 through 3N effluent is applied to the distribution media of a mound system
installed above in -situ soil types 1 through 3 (Table 30-10-1) and R-0 through R-2 (Table
30-10-1A), the linear loading rate may exceed 12 gpd/lin.ft.; subsequently the mound may
be wider than 12 feet.
3. When TL1 through TL3N effluent is applied to mound systems installed above in -situ soil
types 3A through 5 (Table 30-10-1), the suggested linear loading rate is between 3
gpd/lin.ft. and 5 gpd/lin.ft. The maximum width of the distribution media in a mound system
placed above these soil types is 12 feet.
F. The final cover over a mound system must extend at least twelve inches horizontally beyond
the perimeter of the distribution media prior to sloping down to existing grade. The final slope
of the mound must be no greater than three feet horizontal to one foot vertical.
G. The surface of the mounded area must be planted with a suitable vegetative cover.
H. A suggested reference for the design and installation of mound systems is, "The Wisconsin
Mound Soil Absorption System: Siting, Design, and Construction Manual, January 2000".
Note that this is suggested guidance, and where the requirements of this regulation differ from
those in the referenced mound document, the requirements of this regulation will govern in
those cases.
Amend Sec. 30-11-50. - Rock plant filter (constructed wetland) treatment before soil
treatment area.
Remainder of Section — No change.
ARTICLE XII - Design Criteria - Other Facilities
Amend Sec. 30-12-10. - Evapotranspiration and evapotranspiration/absorption systems.
A. Non -Pressurized Drip Dispersal System (NDDS):
1. An NDDS is considered a type of evapotranspiration/absorption system. However as
specific design criteria is provided for an NDDS, they are exempt from the additional
requirements of section 30-12-10 B, C and D.
2. The Colorado Professionals in Onsite Wastewater Guidelines for the Design and
Installation of Non -Pressurized Drip Dispersal Systems (NDDS), September, 2016 is the
procedural guideline in the design of a NDDS and must be followed when an NDDS is
proposed.
3. The width of an NDDS system may be wider than 12 feet.
B. The following section provides general criteria which must be followed when an
evapotranspiration or evapotranspiration/absorption bed is proposed.
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1. The design may only be permitted in arid climates where the annual evaporation rate
exceeds the annual precipitation rate by more than 20 percent, and where site
characteristics dictate that conventional methods of effluent dispersal are not appropriate.
2. The design may only bepermitted in soil types 4, 4A and 5 .
3. The system must be designed by a professional engineer.
4. If data for the Pan Evaporation Rate is provided, it must be multiplied by 0.70, or less, to
obtain the equivalent Lake Evaporation Rate.
5. The width of the bed may be wider than 12. feet.
6. The required capillary or wicking sand must meet the gradation requirements in Table 12-
1 and be approved by the design engineer. This sand is to be covered by a crowned, thin
layer of loamy -sand mix and appropriate vegetation that will assist in drawing the water to
the surface.
7. Adjustment factors as provided in Tables 30-10-2 and 30-10-3 must not be used.
Add Table 30-12-1 Gradation of Wicking Sand for Evapotranspiration Beds (Fine Sand)
Sieve Size
Percent Passing
4
100
40
50-70
200
<15
C. For systems designed strictly as an evapotranspiration bed, the following criteria must be met:
1. Design data to be furnished must include, but shall not be limited to: system dimensions,
distribution system design; specifications of distribution media and wicking sand, liner
material if used, bedding; properties of the soil under the system, vegetative cover, and
a water balance calculation including annual precipitation and storage requirements for
periods of the year when evapotranspiration does not occur.
2. The following formula must be used for determining the minimum area necessary for
total evapotranspiration of septic tank effluent:
Area (in square feet)* = Design flow (in gallons per day) x 586
Lake evaporation rate at the site (in inches per year)
* Additional area may be required based on the annual water balance calculations.
3. Designs will include a rock and pipe, or other Water Quality Control Division approved
proprietary distribution product, with the centerline of the distribution system 6 to 8 feet on
center. A thin non -woven fabric may be placed above the distribution system. Capillary
wicking of the effluent is accomplished by a uniform depth layer of the specified sand
media (capillary wicks), no more than 24 inches deep, placed between and above the
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distribution media. The base of the evapotranspiration bed may be no more than 30 inches
below finished grade.
4. Capillary wicks which penetrate between the distribution system to the bottom of the bed,
must be at least 15 percent of the bed surface area. The wicks must be uniformly spaced
throughout the system.
5. Except for dwellings, if the system is designed for summer use only, the surface area
maybe multiplied by 0.6 to obtain the required area.
D. For systems designed as an evapotranspiration/absorption bed, the following criteria must be
met.
1. Data to be furnished must include, but is not limited to: system dimensions, distribution
system design, specifications of wicking sand, properties of the soil under the
evapotranspiration/absorption bed, provision for vegetation cover, and a water balance
calculation including annual precipitation and storage requirements for periods of the year
when evapotranspiration does not occur.
2. Design will include a rock and pipe, or other Water Quality Control Division approved
proprietary distribution product, with the centerline of the distribution system 6 to 8 feet on
center. A thin non -woven fabric may be placed above the distribution media. Capillary
wicking of the effluent is accomplished by a uniform depth layer of the specified sand
media (capillary wicks) no more than 24 inches deep placed between and above the
distribution media. The infiltrative surface may be no more than 30 inches below finished
grade.
3. Capillary wicks which penetrate between the distribution system to the bottom of the bed,
must be at least 15 percent of the bed surface area. The wicks must be uniformly spaced
throughout the bed.
4. Amount of storage and evapotranspiration capacities may be reduced by the volume of
effluent absorbed by the underlying soil based on the long-term acceptance rate for that
soil type and the formulas provided in section 30-12-10 D.5. below.
5. The following formula must be used for determining the minimum area necessary for
evapotranspiration/absorption of septic tank effluent:
(1) Area (sq. ft.)* = Flow (qpd)
(LTAR + ETR)
a. LTAR refers to the long-term acceptance rate of the underlying soil as provided in
Table 30-10-1 for TL1 effluent.
b. ETR refers to the evapotranspiration rate derived from the following formula:
ETR (gal./day sq. ft.) = Lake Evaporation Rate at the Site (in inches per year)
586
* Additional area may be required based on the annual water balance calculations.
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Amend Sec. 30-12-20. Vaults other than vault privies.
A. and B. — No change.
C. A vault must have a minimum five -hundred -gallon effective volume or be capable of holding
a minimum of the 48 hour design wastewater flow, whichever is larger.
D. thru F. — No change.
Amend Sec. 30-12-30. Vault privies.
A. Effective volume of the vault privy must be no less than four hundred (400) gallons, and it
must be constructed of concrete or plastic. The vaults for privies must meet the structural and
watertightness standards of vaults.
B. A vault privy must be built to include: fly- and rodent -tight construction, a superstructure
affording complete privacy, an earth mound around the top of the vault and below floor level
that slopes downward away from the superstructure base, a floor and a riser of concrete or
other impervious materials with hinged seats and covers of easily cleanable, impervious
material. All venting must be fly -proofed with No. 16 or tighter mesh screening.
C. A signal device is not required for a vault privy.
D. A permit fee, as set by the Board of County Commissioners, shall be required of applicants
for any system that requires only a vault or holding tank. An application for an OWTS permit
must be completed by the owner and a final inspection must be made by the Division with
proper notice as specified in Section 30-4-70 of this Chapter.
Amend Sec. 30-12-40. Incinerating, composting and chemical toilets.
A. The use of an incinerating, composting or chemical toilet will not reduce the required size of
the OWTS as noted in Section 30-8-10.
B. Incinerating and composting toilets may be permitted. Incinerating and composting toilets
shall bear the seal of approval of the NSF or an equivalent test and certification program.
C. Permitting of an incinerating or composting toilet may also be subject to the jurisdiction of a
local agency regulating plumbing or the Colorado Plumbing Board, whichever has jurisdiction
over plumbing in the location.
D. An incinerating or composting toilet may be used for toilet waste where an OWTS is installed
for treating wastewater remaining after removal of toilet waste. Subject to Board of Public
Health or other applicable regulations or codes (e.g., Colorado Plumbing Code if a local code
does not exist), the compartment may be located within a dwelling or building, provided that
the unit complies with the applicable requirements of this Regulation and provided that the
installation will not result in conditions considered to be a health hazard as determined by the
Division. Compartment and appurtenances related to the unit must include fly -tight and
vector -proof construction and exterior ventilation.
E. Incinerating toilets. An approved incinerating toilet must be designed and installed in
accordance with all applicable federal, state and local air pollution requirements and
manufacturer's instructions.
1. Incinerating Toilets Acceptance Requirements
a. Incinerating toilets must meet the requirements of the NSF Protocol P157 and bear
the seal of approval of the NSF or an equivalent testing and certification program.
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b. Incinerating toilets must be operated according to manufacturer's specifications.
F. Composting toilets.
1. Composting toilets must meet the requirements of NSF/ANSI Standard 41 and bear the
seal of approval of the NSF or an equivalent testing and certification program.
2. An approved composting toilet must treat deposits of feces, urine and readily
decomposable household garbage that are not diluted with water or other fluids and are
retained in a compartment in which aerobic composting will occur.
3. The effective volume of the receptacle must be sufficient to accommodate the number
of persons served in the design of the unit installed. The effective volume of the unit must
include sufficient area for the use of composting materials, which must not be toxic to
the process or hazardous to persons and which must be used in sufficient quantity to
assure proper decomposition.
4. Residue from the composting toilet must be removed when it is filled to seventy-five
percent (75/0) of capacity. Residue from the unit must be properly disposed of by
methods recommended by the manufacturer and acceptable to the Division. Disposal
methods must prevent contamination of water and not cause a public health nuisance.
Disposal using solid waste practices is recommended.
5. If a system will be installed where low temperature may be a factor, design and
installation must address the effects of the low temperature.
6. Composting toilets must be operated according to manufacturer's specifications.
G. Portable chemical toilets.
1. A portable chemical toilet may be used by permit from the Division.
2. Use of a portable chemical toilet in permanently occupied buildings is prohibited except
during construction or under emergency circumstances as determined by the Division.
Proper ventilation of a chemical tilet used inside must be required.
end Sec. 30-12-5
atment
rea
rsan
Treatment s stems other than thus ^5 dlschari hig through a soil
filter systems
A. ® No change.
B. Systems that discharge other than through a soil treatment area or a sand filter system must:
1. Be designed by a professional engineer;
2. Be reviewed by the Board of Public Health; and
3. Not pose a potential health hazard or private or public nuisance or undue risk of
contamination.
4. Not allow drainage of effluent off of the property of origin.
C. ® No change.
D. The following minimum performance criteria must be required for all permitted systems
pursuant to this Section:
1. If effluent discharge is made into areas in which the possibility exists for occasional direct
human contact with the effluent discharge, the effluent at the point of discharge must
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meet the minimum treatment criteria of TL3 effluent and specifically adhere to each of
the following standards:
a. The geometric mean of the E._coli density must not exceed fifteen (15) per one
hundred (100) milliliters when averaged over any five (5) consecutive samples, and
no single sample result for E._coli can exceed one hundred twenty-six (126) per one
hundred (100) milliliters.
b. and c. — No change.
2. If the effluent discharge is made into an area so restricted as to protect against the
likelihood of direct human contact with the discharged effluent, the effluent, at the point
of discharge, must meet the treatment criteria of TL2 effluent and specifically adhere to
each of the following standards:
a. The geometric mean of the E._coli density must not exceed one hundred twenty-six
(126) per one hundred (100) milliliters when averaged over any five (5) consecutive
samples and no single sample can exceed three hundred twenty-five (325) E._coli
per one hundred (100) milliliters.
b. and c. — No change.
E. To determine compliance with the standards contained in this Section, the required sampling
frequency for E._coli, CBOD 5 and total suspended solids levels must be performed at least
once per month when the system is in operation and the results submitted to the Division for
compliance with the permit requirements.
F. — No change.
ARTICLE XIII - OPER TUON AND ADNtENANCE eniwww a nn `ntenance
Amend Sec. 30-13-30. Monitoring and sampling.
A. For an OWTS for which monitoring of effluent is required, a delegated third party must collect
and test effluent samples to ensure compliance with the provisions of this Regulation.
B. Sampling may be required by the Division in conjunction with an enforcement action.
C. Any owner or occupant of property on which an OWTS is located may request the Division
to collect and test an effluent sample from the system. The Division may perform such
collection and testing services. The owner or occupant must pay for these services.
1. If the Division or a delegated third party collects and tests effluent samples, a fee not to
exceed that which is allowed by the OWTS Act may be charged for each sample
collected and tested. Payment of such charge must be stated in the permit as a condition
for its continued use.
2. Conditions when the Division can require routine monitoring, including but not limited to:
a. Indications of inadequate performance;
b. Location in sensitive areas; and
c. Experimental systems.
D. Sampling and analysis must be performed according to American Public Health Association,
American Water Works Association and Water Environment Federation: Standards Methods
for the Examination of Water and Wastewater , 21 st edition.
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Add ARTICLE XIV - T CHI ° OL GY REVENV AN } .CCEPTCEeckri- —R
G
Sec. 30-14=10. Technology Review and Acceptance
A. OWTS technologies must either be public domain, including, but not limited to, rock and pipe
distribution systems, sand filters with pressure distribution and mound systems, with criteria
for design, installation, maintenance and use as described in this regulation, or proprietary
products that have received Water Quality Control Division review and acceptance before the
Division may permit them for use, as stated in Section 43.13 of Regulation 43.
B. The Water Quality Control Division must review and provide either comment or acceptance to
the manufacturer for proprietary products in these technology categories:
1. Proprietary treatment products (e.g. treatment systems);
2. Propriety distribution products (e.g. manufactured distribution products or subsurface
dripline);
3. Septic tanks;
4. Others as needed.
Add ARTICLE XV MATER
ALS INCORP
TE
Sec. 30-15-10 Materials Incorporated by Reference
Y RETIE
rn1
ENCEateriaAls4pentad—
Throughout these regulations, standards and requirements by outside organizations have
been adopted and incorporated by reference. The materials incorporated by reference cited
herein include only those versions that were in effect as of April 10, 2017, and not later
amendments to the incorporated material.
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Amend APPENDIX 30-B
SOIL CLASSIFICATION SYSTEM (SOIL -SEPARATE SIZE LIMITS)
SOURCE: USDA NRCS Field Book (pages 2-45)
FINE EARTH
ROCK FRAGMENTS b5o 24"
10 o mm
charmers 1 lager ( stones
boulders
USDA
Clay
Silt
Sand
Gravel
Cob -
bles
Stones
Boulders
fine
co.
fine
co,
v.fi.
fi. i med.
co.
cv6.
fine
medium
coarse
millimeters: 0.0002 .002 mm .02 .05 .1 .25 .5 1 2 mm 5 20 76 250 mm 600 mm
U.S. Standard Sieve No, (opening): 300 140 60 35 18 10 4 (3/4') (3) (10") (25')
International
Clay
Silt
Sand
Stones
Gravel
fine I— coarse
millimeters: .002 mm .02 .20 2 mm 20 mm
U.S. Standard Sieve No. (opening): 10 (3/4)
Unified
Silt or Clay
Sand
Gravel
Cobbles
Boulders
fine
medium co.
fine
coarse
millimeters: .074 .42 2 mm 4 8 19 76 - 300 mm
U.S. Standard Sieve No. (opening): 200 40 10 4 (3/4) (3)
AASHTO
Clay
Silt
Sand ! Gravel or Stones
Broken Rock (angular),
or Boulders (rounded)
fine coarse ,i fine f med. co.
millimeters: .005 mm .074 .42 2 mm 9.5 25 75 mm
U.S. Standard Sieve No. (opening): 200 40 10 (3/8") (1) (3)
phi #: 12 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 .4 -5 .6 -7 -8 -9 -10 -12
Modified
n orth
44....\1\_ lay
I.
►
sand)
bbles
�°°64,-►f—boulders►
I
silt
I-
( 1
►
p,
I
l I S
millimeters: .00025 .002 .004 .008 .016 .031 .062 .125 .25 .5 1 2 4 8 16 32 64 128 256 4092 mm
U.S. Standard Steve No.: 230 120 60 35 18 10 5
64
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BE IT FURTHER ORDAINED by the Board that the Clerk to the Board be, and hereby is,
directed to arrange for Municode to supplement the Weld County Code with the amendments
contained herein, to coincide with chapters, articles, divisions, sections, and subsections as they
currently exist within said Code; and to resolve any inconsistencies regarding capitalization,
grammar, and numbering or placement of chapters, articles, divisions, sections, and subsections
in said Code.
BE IT FURTHER ORDAINED by the Board, if any section, subsection, paragraph,
sentence, clause, or phrase of this Ordinance is for any reason held or decided to be
unconstitutional, such decision shall not affect the validity of the remaining portions hereof. The
Board of County Commissioners hereby declares that it would have enacted this Ordinance in
each and every section, subsection, paragraph, sentence, clause, and phrase thereof irrespective
of the fact that any one or more sections, subsections, paragraphs, sentences, clauses, or
phrases might be declared to be unconstitutional or invalid.
The above and foregoing Ordinance Number 2017-10 was, on motion duly made and
seconded, adopted by the following vote on the 29th day of January, A.D., 2018.
BOARD OF COUNTY COMMISSIONERS
WELD COUNTY, COLORADO
ATTEST:
Steve Moreno, Chair
Weld County Clerk to the Board
Barbara Kirkmeyer, Pro-Tem
BY:
Deputy Clerk to the Board
Sean P. Conway
APPROVED AS TO FORM:
Julie A. Cozad
County Attorney
Mike Freeman
Date of signature:
65
2017-0104
ORD2017-10
Publication: November 8, 2017
First Reading: December 18, 2017
Publication: December 27, 2017, in the Greeley Tribune
Second Reading: January 8, 2018
Publication: January 17, 2018, in the Greeley Tribune
Final Reading: January 29, 2018
Publication: February 7, 2018, in the Greeley Tribune
Effective: February 12, 2018
66
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