HomeMy WebLinkAboutbocc.ord.003.2001 AN ORDINANCE OF THE BOARD OF COUNTY COMMISSIONERS OF PITKIN
COUNTY, COLORADO
PITKIN COUNTY INDIVIDUAL SEWAGE DISPOSAL SYSTEM REGULATION
Ordinance# O1 - L10 3
RECITALS
1. The Board of County Commissioners(BOCC) is concerned about the quality of
surface and ground water in Pitkin County, and realizes the potential impact
individual sewage disposal systems(ISDS)pose to these aquifers.
2. The BOCC realizes the public health impacts of surface and ground water
deterioration as the result of subsurface discharge of waste water.
3. The BOCC recognizes the fact that all areas of Pitkin County cannot be served by
public sewage collection systems, and in such cases,the technically correct method of
sewage treatment is the installation of ISDS.
4. The BOCC recognizes that establishing minimum design standards for ISDS using
sound scientific and technical practices is necessary to assure long-term protection of
surface and ground water in Pitkin County.
5. The BOCC recognizes their ability to adopt ISDS regulations specific for Pitkin
County, using the Colorado "Guidelines On Individual Sewage Disposal Systems,"
Revised 1994, as a minimum standard.
6. The BOCC realizes they can make sections of the Pitkin County ISDS regulation as
strict, or more strict than the Colorado Guidelines.
7. The BOCC realizes it is in the best interest of the County to adopt the specific
changes listed in Exhibit A attached.
NOW THEREFORE BE IT ORDAINED by the Board of County Commissioners
of Pitkin County, Colorado that the PITKIN COUNTY INDIVIDUAL SEWAGE
DISPOSAL SYSTEM REGULATIONS, Revised 2001, listed in Exhibit A are
adopted and will become a section in the Pitkin County Code. This ordinance replaces
and repeals Ordinance 97-41.
After adoption, this Regulation and Ordinance may be published by title only.
INTRODUCED, FIRST READ,AND SET FOR PUBLIC HEARING AT THE
REGULAR MEETING ON THE 1 OTH DAY OF JANUARY, 2001.
NOTICE OF PUBLIC HEARING PUBLISHED IN THE ASPEN TIMES ON
THE 2e DAY OF JANUARY, 2001.
APPROVED AND ADOPTED AFTER SECOND READING AND PUBLIC
HEARING ON THE 14TH DAY OF FEBRUARY, 2001.
PUBLISHED AFTER ADOPTION IN THE ASPEN TIMES ON THE 24Tm DAY
OF FEBRUARY, 2001.
ATTEST: BOARD OF COUNTY COMMISIONERS
OF PITKIN COUNTY, COLORADO
by: I*. 44(a V1
JeAAette Jones Michael C. Ireland, Chaimfan
puty Clerk and R order '
Date:
APPROVED AS TO FORM: MANAGER APPROVAL:
John Ely Hilary S t
Coun tomey Acting County Manager
APPROVED AS TO CONTENT:
Thomas S. Dunlop,Director -�
Pitkin County Environmental Health Department
Mb-G:/ISDS/REGS/OOREGS-ORDINANCE.DOC
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INDIVIDUAL SEWAGE DISPOSAL SYSTEM
REGULATION
PITKIN COUNTY
REVISED 2001
Effective date: April 15, 2001
Pitkin County Environmental Health Department
0405 Castle Creek Road, Suite 10
Aspen, CO 81611
TABLE OF CONTENTS
Page
Article1 Scope and Purpose......................................................................................................................................5
Section 1-1 Declaration and Purpose
Section 1-2 Regulation Coverage,Systems Requiring Both State and Local Approval
Section 1-3 Systems Required to Connect to Public Sewer
Article2 Definitions....................................................................................................................................................7
Article 3 Who Must Obtain an ISDS Permit..........................................................................................................9
Section 3-1 Construction Requiring a Permit
Section 3-2 Permit Required for Expansion or Increase in Bedrooms
Section 3-3 Certificate of Occupancy Requiring LSDS Final Approval
Section 34 Adequate Sewage Facilities Required
Section 3.5 Systems Required for Cabins
Article 4 Procedure for Obtaining an ISDS Permit............................................................................................11
Section 4-1 Summary of ISDS Application and Permit Process
Section 4-2 Pre-application Conference with the Department
Section 4-3 Water Well Drilling
Section 4-4 Soil Tests
Section 4-5 Building Permit Application
Section 4-6 Submission of ISDS Application
Section 4-7 Issuance of Permit by the Department
Section 4-8 Inspections of the System
Section 4-9 Final Approval of Permit and Certificate of Occupancy
Section 4-10 Permit Application Requirements and Procedures-General
Section 4-11 Application Review
Section 4-12 Additional Evaluation
Section 4-13 Additional Hydrological,Geological,Engineering or other Information
Section 4-14 Determination
Section 4-15 Inspection Stages
Section 4-16 Access to Site
Section 4-17 Water Quality Control Division Authority to Administer and Enforce
Section 4-18 Primary Enforcement Responsibility
Section 4-19 Experimental Systems
Section 4-20 Prohibition of ISDSs in Unsuitable Areas
Article 5 Soil Tests....................................................................................................................................................17
Section 5-1 Location
Section 5-2 Dimensions
Section 5-3 Procedure
Section 5-4 Calculations
Section 5-5 Performance of Percolation Tests
Section 5-6 Alternate Percolation Tests
Section 5-7 Soil Profile
Section 5-8 Water Table
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Article6 Types of Systems Allowed.....................................................................................................................19
Section 6-1 Situations Requiring Engineered Design
Section 6-2 Engineered Systems
Section 6-3 Experimental Systems
Article 7 Design Requirements for All Types of Systems................................................................................21
Section 7-1 Flow Used for Design
Section 7-2 Persons Per Dwelling
Table I Amounts of Sewage for Various Types of Uses
Section 7-3 Minimum Horizontal Distances Between Components of a System and Physical Features
Table II Minimum Horizontal Distances in Feet Between Components of a Sewage Disposal System
and Pertinent Physical Features
Article 8 Tank Design Requirements....................................................................................................................27
Section 8-1 Septic Tank Design Criteria
Section 8-2 Tank Size
Section 8-3 Septic Tank Design Criteria
Section 8-4 Aerobic Sewage Treatment Systems
Section 8-5 Method of Aeration
Article 9 Inspection and Maintenance..................................................................................................................29
Section 9-1 Responsibility
Section 9-2 Service Label
Section 9-3 Maintenance and Cleaning
Table Maintenance and Cleaning
Section 9-4 Monitoring and Sampling
Section 9-5 Disposal of Waste Materials
Section 9-6 No Discharges is Permitted that Does Not Comply with Rules and Regulations
Section 9-7 Termination of Use of System
Article10 Component Design Criteria................................................................................................................31
Section 10-1 Design Features
Section 10-2 Installation
Section 10-3 Optional Design Features
Table Dosing Frequency
Article 11 Design Requirements for Conventional Systems............................................................................35
Section 11-1 Absorption Area Size Calculations
Section 11-2 Reduction in Size of System
Section 11-3 System Size Increases
Section 11-4 Construction/Design Requirements for Conventional Systems
Article 12 Design Requirements for Engineered Systems...............................................................................39
Section 12-1 General
Section 12-2 Area Size Calculations
Table Long Term Acceptance Rates
Section 12-3 Construction/Design Requirements
Section 12-4 Mound Systems
Section 12-5 Sand Filter Systems
Section 12-6 Evapotranspiration(ET)Disposal Systems
Table Gradation Requirements for Sand Used in ET Beds
Section 12-7 Wastewater Ponds
Section 12-8 Constructed Wetland Treatment
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Article 13 Design Requirements for Other Facilities.........................................................................................45
Section 13-1 Gray Water Systems
Section 13-2 Vaults
Section 13 3 Vault Privy
Section 13-4 Incineration and Chemical Toilets
Section 13-5 Business,Commercial,Industrial,Institutional or Multi-family Dwelling Waste Systems
Section 13-6 Composting Toilets
Section 13-7 Recycling Systems that Recycle Treated Waste Water
Section 138 Manufactured Units Using Mechanical Apparatus for Treatment of Sewage
Section 13-9 Experimental Systems
Appendix 1 Systems Not Using Soil Absorption or Sand Filter,and Non-discharging Systems...........47
Appendix 2 Effluent Discharged to State Waters...............................................................................................49
Appendix 3 Appeals and Penalties........................................................................................................................51
Appendix 4 Proportions of Sand,Silt and Clay In the Basic Soil-Textural Classes...................................53
Index .........................................................................................................................................................................55
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Article 1: Scope and Purpose
1-1 Declaration and Purpose
The purpose of this regulation is to preserve the environment and protect the public health;to eliminate and
control causes of disease,infection,and contamination;and to reduce and control pollution of the air,land
and water. The Min County Board of Health therefore declares it to be in the public interest to establish
minimum standards,rules,and regulations for Individual Sewage Disposal Systems(ISDSs)in Pitkin
County. This regulation provides the authority for the administration and enforcement of such minimum
standards,rules,and regulations.
This regulation applies throughout Pitkin County,and applies to LSDSs having less than an average daily
flow of ZOO gallons per day.This regulation governs all aspects of permits,performance,location,
construction,alteration,installation,and use of these systems.
The Pitkin County Board of Health declares that its policy is to require the use of public sewer systems
whenever feasible. Its policy is to limit the installation of ISDSs to areas where public sewer systems are not
feasible.
1-2 Regulation Coverage,Systems Requiring both State and Local Approval
An ISDS with a design capacity greater than or equal to an average daily flow of ZOOO gallons per day must
be approved and permitted by the Colorado Department of Public Health and Environment Water Quality
Control Division("Division'). However,local ISDS regulations then govern all other aspects of permits,
performance,construction,alteration and installation. For all systems of any capacity,the owner or agent
must submit an ISDS application to the Pitkin County Environmental Health Department,("Department")
The Department will then determine whether state approval is necessary.
1-3 Systems Required to Connect to Public Sewer
The Department may not issue an ISDS permit if the property is in a municipality or special district that
provides sewer service,except where the municipality or district determines sewer service to the property is
not feasible. The Department may require a letter from the municipality or special district stating public
sewage collection is not feasible,so the Department may issue an ISDS permit
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Article 2: Definitions
Absorption bed-a subsurface soil absorption area that is wider than three feet,that provides for effluent to
seep,leach or infiltrate into the soil.
Absorption System-a system for the treatment of sewage in an individual sewage disposal system by means
of absorption into the ground.
Absorption Trench-trenches not over three feet in width in which sewage effluent seeps,leaches,or
infiltrates into the soil
Aerobic Sewage Treatment System-an ISDS in which the addition of air or oxygen maintains the action of
the system.
Bedrock-the solid undisturbed rock at the surface or beneath surface deposits or a consolidated rock
formation of impervious material that may be jointed,fractured,or deteriorated.
Bedroom -a room suitable for sleeping is a room greater than 70 square feet and no dimension less than 7
feet;with or without a closet;which has direct or indirect access to a full or 3h bath.
Chamber-constructed of multiple sized-high-density polyethelene molds which are impervious to all
components of wastewater. There is an interior storage capacity with an open bottom area.
Composting Toilet-a unit that connects to a compartment or a vault that receives waste materials and will
reduce waste by aerobic decomposition.
Constricted Wetland-A system that uses wetland plants to provide secondary treatment of wastewater
through biological,physical,and chemical processes.
Department-The Pitkin County Environmental Health Department.
Dispersal System-a system that disposes effluent by a method not using the treatment capability of the soil.
Distribution Box-a watertight chamber that receives waste water from a septic tank or other primary
treatment unit and that distributes effluent evenly throughout the absorption system.
Division-The Water Quality Control Division of the Colorado Department of Public Health and
Environment.
Dosing Tank-a tank that stores wastewater from a septic tank and feeds it to an absorption area at a high
rate periodic discharge.
Drywell-a soil absorption system filled with gravel and containing a system of distribution that is designed
on the basis of sidewall and bottom absorption area.
Environmental Health Specialist-A person trained in physical,biological,and/or environmental health
science to carry out education and inspection duties in the field of environmental health.
Evapotranspiration System-a type of dispersal system that uses liquid evaporation and transpiration by
vegetation as a means of effluent disposal.
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Experimental System-a particular design or type of system based upon improvements,or development in
the technology of sewage disposal and not otherwise provided for in these regulations.
Filter-Non-corrodible screen,which limits the size of solids that my leave a septic tank or pumping
chamber. The filter must be accessible for cleaning and replacement from the ground surface.
Individual Sewage Disposal System,ISDS,or"system"-a system for collecting,treating,or disposing of
sewage that is not connected to a sewage treatment works.
Percolation Tests("Perc tests")-a subsurface soil test at the depth of a proposed absorption system or
similar component of an ISDS to determine the water absorption capability of the soil.The results of the
percolation test give the number of minutes it takes one inch of water to be absorbed.
Privy-a structure allowing for the disposal of excreta not transported by a sewer and that provides privacy
and shelter and prevents access to the excreta by flies,rodents,or other vectors.
Sand Filter-a subsurface system that uses wastewater filtration or absorption or both,and that contains an
intermediate layer of sand as filter material.
Seepage Bed-See Absorption Bed
Seepage Pit-a soil absorption system containing a structural internal void surrounded by rock and designed
on the basis of sidewall absorption area.
Septic Tank-a watertight,accessible covered receptacle designed and constructed to receive sewage from a
building sewer.It must also settle solids from the liquid,digest organic matter,store digested solids through
a period of retention,and allow the clarified liquids to discharge to other treatment units for final disposal.
Serial Distribution-an arrangement of absorption trenches,seepage pits or seepage beds that retain effluent
in one part to use the absorption capacity of that component before flowing into a succeeding component.
Sewage Treatment Works-a facility for treating,neutralizing,stabilizing,or disposing of sewage,that has a
designed capacity to receive more than two thousand gallons of sewage per day,unless designed as an
absorption system. The term"sewage treatment works"includes appurtenances such as interceptors,
collection lines,effluent line,and the outlet sewers,pumping stations,and related equipment.
Vault-a watertight,covered receptacle,designed to receive and store excreta or wastes either from a sewer
or from a privy that is accessible for the periodic removal of its contents.
Water Supply-minimum daily water supply for domestic house shall be.07gallons/minute/person which is
100 gallons/person/day. There must be storage or yield capable of a 24hour supply(not including fire
protection or irrigation).
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ARTICLE 3: Who Must Obtain An ISDS Permit
The regulation requires permits in the following situations and the following provisions apply:
3-1 Construction Requiring a Permit:The building department may not issue a permit to construct or
remodel a building or structure that is not connected to a public sewer,until a permit for an ISDS has been
issued by the Department.
3-2 Permit Required for Expansion or Increase in Bedrooms:An ISDS permit is required for expanded use
of an existing system,including the addition of bedrooms or rooms that may be used as bedrooms in the
future,or the conversion of other rooms into bedrooms or any other modification affecting water use. The
Department will review plans for alterations to dwellings to determine if it is necessary to expand the ISDS
system.
3.3 Certificate of Occupancy Requiring ISDS Final Approval:The building department cannot issue a
certificate of occupancy for the use of a building that is not served by a public sewer system until the
Department has approved the design of the ISDS,performed a final inspection of the ISDS,and issued a final
permit.
3JI Adequate Sewage Facilities Required:No one may construct or maintain any dwelling or other
occupied structure that does not have adequate facilities for the sanitary disposal of sewage in a way that will
not endanger the public health.
3S Systems Required for Cabins: All types of buildings must have ISDSs that comply with this regulation.
For small cabins with running water,a composting toilet or vault privy may be used in conjunction with a
gray water system including a septic tank,sized for the number of bedrooms in the cabin.For small cabins
without running water,alternative systems,such as a composting toilet or vault privy,may be used.
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Article 4: Procedure for Obtaining an ISDS Permit
4-1 Summary of ISDS Application and Permit Process:The Department will accept and begin review of an
application only when the application contains all pertinent information. This includes,among other
information,soil percolation and profile hole data,complete site information and house plans,and an ISDS
designed by a Colorado Registered Professional Engineer(RPE),someone working under the supervision of
a RPE,or an individual performing engineering services for themselves. Note:an individual may provide
ISDS engineering services for themselves provided the dwelling the ISDS serves is his/her primary
residence.
4-2 Pre-application Conference with Department-At this time the applicant will receive the necessary
permit applications and information. The Department will assist the applicant with special considerations
that may apply to a given lot and may schedule a time to visit the site with the applicant to provide further
assistance.
The applicant may schedule this conference immediately.
4-3 Water Well Drilling:Before the Department can issue an ISDS permit,the owner must drill the lot's
well. Since this is time-consuming and difficult in certain times of the year,and may require road
construction,this should be the first step undertaken by the applicant. For rural and remote locations the
applicant will be required to meet with the Department to determine applicability to their specific case,as the
water supply may be determined after issuance of the ISDS permit
4-4 Soil Tests:The applicant will need to obtain soil percolation bests and soil profile information.The
percolation best must be performed by or under the supervision of a Colorado RPE. See Section 5. The
owner or agent must submit percolation test results,and soil profile information to a Colorado Registered
Professional Engineer so a system can be designed. As a general policy,soil besting is permitted from April
15 through November 15.
4-5 Building Permit Application The applicant must submit the building permit application separately to
the building department. As part of the review of the building permit,the Department will make sure that
an ISDS permit has been issued.
4-6 Submission of ISDS Application The applicant will need to submit a completed ISDS permit
application to the Department. See 4-11 Permit Application Requirements and Procedures
4-7 Issuance of Permit by the Department The Department will process a completed application in a timely
manner. If the application is incomplete,or if there are problems or inconsistencies with any of the submitted
information,additional time will be required. Construction cannot begin on the system until the Department
has issued a permit.
4-8 Inspections of System During construction of the ISDS system, the RPE who designed the system,and
the Department will inspect it to ensure it is constructed as required by these regulations.
4A Final Approval of Permit and Certificate of Occupancy:Once the system is constructed and completed
according to the terms of the permit,the permit will be finaled. At that time,the Department can approve
the certificate of occupancy.
4-10 Permit Application Requirements and Procedures-General
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Specific steps include the following:
4-10.1 Permit Application required:
NOTE: SEPTIC PERMIT APPLICATIONS CANNOT BE ACCEPTED UNTIL ALL OF THE
INFORMATION BELOW IS INCLUDED.
The soils test and system design must be done by a Colorado Registered Professional Engineer. You
should plan to meet with the RPE at your site to discuss where the soils tests should be done to meet all
of the County regulations and where you want to put your house. The RPE will be your contact for issues
you want to discuss about your system's size and location. Each box should be checked to indicate the
following have been submitted before the application can be accepted.
ElEnv. Health has been called to look at profile hole
ElCompleted application form
Engineer design stamped by a RPE registered in the State of Colorado. (One set)
Site map must include location of all existing and proposed wells within setback distances
(including on surrounding properties), contour intervals, all proposed and existing buildings,
property lines, ditches, slopes of greater than 15% in the area of the drain field, water lines,
sprinkler systems, springs, suction (irrigation) lines, drinking water cisterns, drain tiles, irrigation
ditches, lakes, ponds, water courses, streams, floodplains, floodways, dry gulches, or existing
septic systems. This must include all such features on neighboring properties within setbacks.
i Complete building floor plans. Floor plans should be 11x17. (One set)
Proof of adequate water supply: (Well must be drilled before septic permit can be Issued.):
13 For private wells,recent well driller's pump test showing gpm actually produced,well permit
showing legal supply. The minimum yield from the well or water storage shall be .07
gallons/minute/person which is 100 gallons/person/day. There must be storage or yield capable of a
24-hour supply for domestic purposes only(not including fire protection or irrigation).
For community systems, proof there is adequate water for all houses served by the system.
Proof of adequate water quality with Bacteriology test: Aspen Consolidated Sanitation District and
Snowmass Water&Sanitation District perform this test locally.
11771 Percolation tests
Lj
All ISDS Permit fees are$330 to cover first six hours of processing. Hourly rate of$65 will be
13 charged beyond first six hours, up to$1,000. Tank only fee$110. Check payable to: PCEHD.
ElCopy of county approval (1041 approval, subdivision approval, etc.)
You must obtain written approval from Community Development before submitting this
application If your septic system is outside the building envelope and any part of the
system is more than 30" above grade.
A WAIVER IS AVAILABLE FOR SUBMITTING A BUILDING PERMIT APPLICATION
PRIOR TO OBTAINING AN INDIVIDUAL SEWAGE DISPOSAL SYSTEM PERMIT.
Please ask the Community Development Department or Environmental Health Department for
further information.
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Prior to the start of any work in conjunction with the installation,alteration,or repair of a system,the owner
or applicant must schedule a time for the profile hole to be inspected by this Department The next step is to
submit a written application to the Department and the Department must have issued a permit prior to the
start of any work.A copy of this permit must be kept on site. The applicant must provide the information
requested on the application form. The issuance of a permit and specifications of berms and conditions
therein shall not constitute assumption or create a presumption that the Department or its employees may be
liable for the failure of any system nor act as a certification that the equipment used in the system or any
component thereof used in its operation or that the system for which the permit was issued insures
continuous compliance with these regulations or any terns and conditions of a permit An ISDS must be
designed by a Colorado Registered Professional Engineer(RPE)or someone under his/her supervision. An
ISDS may also be designed by individuals who perform engineering services for themselves,acting as
owner/builder,provided the dwelling the ISDS serves is his/her primary residence. On an annual basis,the
Department will provide information on any new systems or components that have been certified and may
be used,or new procedures that have been developed and approved.
If the ISDS is designed by the owner/builder,he/she must sign an acknowledgment assuming full
responsibility for costs or delays incurred because of errors resulting from his/her lack of knowledge of
the pertinent Regulation,or failure to properly design and build an ISDS in conformance with the
Regulation.
4-10.2 Permit fee:A fee in the amount necessary to cover the operational expense of the Department to
administer this program is required of applicants for an ISDS permit The minimum fee for processing an
application will be$330 if processing takes 6 hours or less. An hourly fee of$65 will be assessed if processing
the application takes longer than 6 hours,up to the cap created by State Law($1000). The initial$330 will be
payable when the application is received by the Department Additional fees will be payable prior to issuing
a permit or a final inspection. The fee for processing an application to replace only a septic tank or dosing
tank will be$110,with$65/hour assessed if processing takes longer than 2 hours. The fee is determined by
the cost to the Department of processing applications during the preceding calendar year.There is no permit
fee for portable toilets.
4-10.3 Waiving permit fees:The Department will waive the permit fee providing the deed states the project
is 100%affordable housing. Fees may be waived for other types of applications as provided by ordinance of
the Pitkin County Board of Commissioners.
4-10.4 Changes in system:Any change in plans or specifications of the ISDS or building or use after the
permit has been issued invalidates the permit unless written approval is secured from the Environmental
Health Specialist for such changes.
410.5 Incomplete or incorrect information Any significant change in information provided in the
application after the permit has been issued invalidates the permit unless written approval is secured from
the Environmental Health Specialist for such changes.
4-10.6 Permit expiration An ISDS permit expires six months after the date of issuance if construction has not
commenced unless the Department has given written approval for an extension. If no change is made in the
proposed system or buildings,and no new site inspection is required,no additional fee will be charged.If
minimal additional work is required,the permit fee will be prorated.
4-10.7 Appeal of permit denial:If the Department denies an application for an ISDS permit the applicant
may request a hearing before the local Board of Health.
4-10.8 Repair permits:The Department may issue a repair permit to the owner or occupant of property on
which a system is not functioning properly. Application for a repair permit must be made by the owner or
occupant to the Department within two business days after observing that the system is not functioning
properly,or within two business days after receiving notice from the Department that the system is not
13
functioning properly,or that it otherwise constitutes a nuisance or a hazard to public health. Cost of a repair
permit will be the same as defined in 4-10.2.
4-10.9 Notice of violation of malfunctioning system:When the Department learns that a system is not
working properly,it will issue a notice of violation(NOV). The NOV will state the violation,set a deadline
for repairing the system and discontinuing use of the failed system,and will note that if the owner fails to
comply,a cease and desist order will be issued. The repair permit will provide the applicant a reasonable
period of time to make repairs. The deadline may be extended for good cause,in the event repairs can not be
completed in the period stated in the repair permit,through no fault of the owner or occupant. At the end of
that period the applicant must have the system inspected by the Department to make sure it is functioning
properly.
4-10.10 Cease and Desist orders: After a hearing conducted by the Environmental Health Director,the
Environmental Health Specialist may issue an order to cease and desist from the use of any system that is
found by the Environmental Health Specialist not to be functioning properly or is found to constitute a
hazard to public health,or has not otherwise received timely repairs. The order shall require that the owner
or occupant bring the system into compliance or eliminate the health hazard in a reasonable period of time,
not to exceed thirty days,or thereafter cease and desist from the use of the system. A cease and desist order
issued by the Department in the county where the system is located is reviewable in the district court for a
petition filed not later than ten days after the order is issued.
4-10.11 Licensing of systems contractors and cleaners:The local Board of Health may adopt rules providing
for licensing of systems contractors or cleaners.
4-11 Application Review.
After receiving a completed application for an ISDS permit,the Department will review the application
based on:
4-11.1 Inspection of the premises,unless previously inspected.
4-11.2 Evaluation of subsurface conditions.
4-11.3 Verification of potable water.
4-11.4 Determine the suitability of the site based upon verification of the ground water table,suitable soil,
depth to bedrock,ground slope and distances from pertinent physical features.
4-11.5 Verify compliance with Pitkin County ISDS Regulations.
4-12 Additional Evaluation:When the Environmental Health Specialist has determined that the
Department does not have sufficient information for evaluation of an application or a system,the
Environmental Health Specialist may require additional tests or documentation
4-13 Additional Hydrological,Geological,Engineering or other Information:When specific evidence
suggests undesirable subsurface conditions may exist,the Department may require the applicant to submit
additional hydrological,geological,engineering or other information provided by a Colorado registered
professional engineer(RPE)or geologist This requirement shall not prejudice the right of the Department to
develop its own information from its own source.
4-14 Determination:After reviewing the application,the engineer's design(or the owner/builder design)
of the proposed ISDS,site inspection,test results and other required information, the Department will
inform the applicant if the proposed system is in compliance with the regulation.
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4-15 Inspection Stages:The ISDS permit will note the times when inspections are required,such as an initial
site visit,and before covering various system components. Before the owner is allowed to use the system,the
owner's agent or the systems contractor must provide the Department with notice that the progress of the
work has been sufficiently completed to allow inspection to determine if all work has been performed in
accordance with the permit requirements and these regulations. The system may not be covered and the
final approval may not be issued until the Environmental Health Specialist has performed a final inspection,
unless the health officer gives written approval to the owner to cover the system. The design engineer must
provide the Department with proof that a final inspection was done by the engineer. A final as-built
drawing of the system is required for all ISDSs installed in Pitkin County prior to final approval.
If an applicant requests a Department inspection,and upon arrival the system or components are not
ready to be inspected,the owner will be billed for the cost of the unnecessary inspection at the rate of$65
each time.
4-16 Access to Site:To enforce these Hiles and regulations and the terms and conditions of any permit
issued,the Environmental Health Specialist is authorized to enter upon private property at reasonable times
to determine if the ISDS is functioning in compliance with state laws,these regulations,and the terms and
conditions of any permit issued and to inspect and conduct bests in evaluating any permit application. The
owner or occupant of every property having an ISDS shall permit the Environmental Health Specialist access
to the property to conduct required tests,take samples,monitor compliance,and make inspections.
4-17 Water Quality Control Division Authority to Administer and Enforce:Wherever the term local Board
of Health,Department,or Environmental Health Specialist is used in these guidelines,said terms shall also
include the Colorado Department of Public Health and Environment or its designated authority for the
purposes of administering and enforcing the provisions of these guidelines as Colorado Department of
Public Health and Environment Regulations where necessary to protect the public health and environment.
4-18 Primary Enforcement Responsibility:The primary responsibility for enforcement of this regulation
shall lie with the Department.
If a Department or local Board of Health fails to administer and enforce the provisions of Article 10,Title 25,
C.R.S.,the Division may assume such functions of the Department or Board of Health as may be necessary to
protect the public health and environment. (25-10-109)
4-19 Experimental Systems:The Board of Health may approve an application for a type of system not
otherwise provided for in these regulations only if the system has been designed by a Colorado RPE,and
only if the application provides for the timely installation of a backup system of a type described in this
regulation if the experimental system fails. The local Board of Health may not arbitrarily deny any person
the right to consideration of an application for such a system and shall apply reasonable performance
standards in determining whether to approve an application.
4-20 Prohibition of ISDSs in Unsuitable Areas:The local Board of Health may conduct a public hearing,
after written notice to all affected property owners as shown in the records of the county assessor and
publication of notice in a newspaper of general circulation at least ben days prior to the hearing,to consider
the prohibition of permits for ISDS systems in defined areas that have or are subdivided for a density of more
than two dwelling units per acre. The local Board of Health may order such prohibition upon a finding that
the construction and use of additional ISDSs in the defined area will constitute a hazard to the public health
or the environment. In such a hearing,the local Board of Health may request affected property owners to
submit engineering and geological reports concerning the defined area and provide a study of the economic
feasibility of constructing a sewage treatment works.
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16
Article 5: Soil Tests
5-1 Location:At least 3 soil percolation tests are required in the area where the absorption system is to be
located. They must be spaced uniformly over the proposed area,but there must be at least one(1)test hole in
every soil texture type in the area and in every twelve hundred(1200)square foot area of the absorption
system.
5-2 Dimensions:The percolation test holes should be six(6)inches in diameter,and no less than four(4)
inches and no greater than twelve(12)inches in diameter where prohibitive soil or geological conditions
exist The holes must end at the depth of the proposed absorption system. The percolation tests must be
done in the soils that comprise the 4 feet of acceptable soils beneath the bottom of the absorption field.
5-3 Procedure:Percolation test holes must be filled with water to a depth of 14 inches or more for at least 8
hours,but not more than 24 hours,before doing the percolation test. They must be refilled with wafter if
necessary to a depth of at least 14 inches prior to final measurement. The time for the water to drop one inch
within the lower six(6)inches of the percolation best hole is measured. The applicant must report the
percolation rate in minutes per inch drop.
5-4 Calculations:The percolation rate is the average rate of the percolation bests after the rate has stabilized
in all the test holes in the proposed absorption area.
5S Performance of Percolation("Perc")Tests:The percolation test must be performed by or under the
supervision of an RPE or by an Environmental Health Specialist of the Department unless adequate tests
previously performed by an RPE are submitted with the application for a permit The Environmental Health
Specialist may request additional percolation tests if the results are conflicting or questionable.
If the applicant demonstrates to the satisfaction of the Department that the system is not dependent upon soil
absorption,the requirement for percolation bests may be waived.
5-6 Alternate Percolation Tests:Other soil test procedures such as soil analysis may be approved by the
Environmental Health Specialist if the test results of alternate procedures meet or exceed those determined
using the test procedure detailed in this article.
5-7 Soil Profile:One soil profile hole must be drilled or dug to provide observation of the soil profile in the
area of the soil absorption system. The hole must be prepared at least eight(8)feet deep. The hole must be
prepared so as to provide identification of the soil profile four(4)feet below the bottom of the soil absorption
system. (The hole may be terminated when groundwater or bedrock is encountered.) This Department must
be notified and given an opportunity to look at the hole.
5.8 Water Table: The system must be designed to maintain a 4 foot separation from seasonally high ground
wafter.
Any LSDS that does not comply with the provisions of this regulation regarding mummun separation
between the maximum seasonal level of the groundwater table and the bottom of an absorption system may
not be permitted to remain in use.
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18
Article 6: Types of Systems Allowed
61 Situations Requiring Engineered Design: In all situations involving the design of a new ISDS or
design for a repair of an ISDS,a Colorado Registered Professional Engineer(or owner/builder) must
design the system. The Department will review the design and upon acceptance,issue the necessary
permit to construct the system.
The RPE will be expected to perform periodic inspections of the construction when necessary,and
perform a final inspection with a letter being sent to the Environmental Health Department stating the
system has been installed according to approved plans or with approved modifications. A final approval
of the permit by the Department will not occur until the letter has been received from the engineer. In the
case of an owner/builder design,he/she must submit an as-built drawing before a final approval is given
by the Department.
6►2 Engineered Systems:The following types of systems require approval from the Department and
require design by a Colorado RPE. *System designs denoted with an asterisk cannot be designed by an
owner/builder unless he/she is a Colorado RPE.
• pipe and gravel systems
• chambered systems
• mound systems*
• sand filter systems*
• evapotranspiration(ET)systems*
• wastewater ponds*
• wetlands systems*
• systems that discharge into the air or on the ground's surface*
• aerobic treatment systems*
6-3 Experimental Systems:See section 4-19
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20
Article T: Design Requirements For All Types of
Systems
7-1 Flow Used for Design:Maximum flow or Design Flow is 175 percent of average daily flow and is the
basis for design purposes.In no event may the system be designed for a lesser capacity than the anticipated
maximum daily sewage flow or treatment requirements of the sewage or wastes in the system.
7-2 Persons Per Dwelling:A minimum of two persons per bedroom must be used to calculate the sewage
flow for dwellings and mobile homes,with a minimum of four people/dwelling used. However,for a
dwelling unit of less than 700 square feet of living area,the field size is based on the actual bedroom count A
room that is likely to be used as a bedroom during the life of the building is considered a bedroom for
purposes of ISDS system sizing.
The following table must be used to determine average daily flow of sewage for different types of uses,and
actual flow metering data may be used to further identify water use patterns:
21
TABLE
AMOUNTS OF SEWAGE
FOR VARIOUS TYPES OF USES
PE OF ESTABLISHMENT GALLONS/PERSON/DAY
(AVERAGE)
(UNLESS OTHERWISE STATID
evidential
Single-family dwe1lmgs<2,000 sq.ft* 75
Separate Distribution of Flows-Individual Residential use for single
dwellings<2,000 sq,ft.
Bath Shower 14.7
Dishwasher 1.8
Kitchen sink 4.4
Additional for garbage grinder 1.4
Laundry washer 195
Lavatory 8.4
Toilet 24.8
15ingle Family dwellings of>2,000 sq.fL but<6,000 sq,fL* 100
Single Family dwellings of>6,000 sq.ft.* 130
Horse Barn with washing facilities allons/horse/day) 50
Hotels and Motels-per room 50
without private baths
Hotels and Motels-per room 75
with private baths
Multiplie-fimuly,dwellings or apartments 75
Bmrding and Rooming houses 50
Mobile Home Parks 75
s 300
ommerrial
Airports 5
employee) 10
Barber and Beauty Shops 100
chair
Bowling Alleys 5
lane-toilet wastes only)
Bus Service Areas 5
not including food
Country clubs
member 30
em 1 ee 20
Dentist offices 50
non-wet chair
Doctors offices doctor 250
Fairgrounds 5
(per person attendm
Factories and plants
exclusive of industrial wastes
employee per 8-hour shift no,showers 20
employee per 8-hour shift-showersprovided) 35
Food service establishments
seat
Restaurant 1 or 2 meals 50
24-hour Restaurant 75
Restaurant with paper service only 25
Additional for bars and cocktail lour es 30
22
Drive-in Restaurant 50
car space)
Kennels do 30
Laundries,selfservhrn 400
mmmerdal waster)*'
Office Buildings 15
ern lo ee per 8-hour shift
tares and Shopping Centers .1
square foot of Retail space)
vice Stations 250
toilet fixture)
tediums,Race Tracks,Ball Parks 5
seat)
eaters(Movie,Indoor,or Auditorium 5
ork or construction camps semi- t-with flush toilets 50
ork or construction cam semi- t-without flush toilets 35
nstitudonal does not include kitchen wastewater flows)
urches rmt inch food 5
'tale bed 250
ursin Haines bed s 100
oo1s,Boarding 100
Schools,Day 15
without cafeteria,gym or showers
with cafeterias,no am or showers 20
with cafeterias,gym and showers 25
additional for school workers 15
Rtaeational and Seasonal
day no meal served 15
L"ury Resort 125
Resort(night and day) 50
Cam d seasonal occupancy unit "' 50
Public Park(during hours when park is open)
-flush Toilet 36
facture per hour
-Urinal 30
facture per hour
Shower 100
fixture per hour
-Faucet 15
(per fixture per hour
5winuning pools and bathhouses 10
ravel trailer parks 50
with individual water and sewage hooka -per unit "
without individual water and sewage hooka -per unnit " 50
• Square feet is the total living area only.
Count each washing machine additionally.See commercial laundries above.
7-3 Minimum Horizontal Distances Between Components of a System and Physical Features: Minimum
horizontal distances from the various components of a system to terrain features shall be in accordance with
the following'Table of Minimum Horizontal Distances". Where soil,geological,nearness to steep
riverbanks,or other conditions warrant,the Department may require greater distances.
Wells,springs or potable water supply suction lines and all other constructed units listed in the Table must
be located in accordance with the minimum distance requirements provided in the table.
23
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NOTE:The Department may require greater distances where warranted. For repair or upgrading of
existing systems where the size of the lot prevents meeting these distances,the repaired facility may not be
closer to water supply components than the existing facility.
(1) Crossings from these distances may be permitted if the drinking water or wastewater pipe is
encased for at least ten(10)feet on each side of the crossing or place where components are closer than
specified in the table. Pipe of Schedule 40 rating or better must be used,of sufficient diameter to easily slide
over and completely encase the line. Ridged end caps of at least Schedule 40 rating must be glued or secured
in a watertight fashion to the ends of the encasement pipe. There must be a hole of sufficient size to
accommodate the pipe in the lowermost section of the ridged cap so that the conveyance pipe rests on the
bottom of the encasement pipe. The area in which the pipe passes through the endcaps must be sealed with
an approved underground sealant compatible with the piping used.
(2) Add 8 feet additional distance for each 100 gallons per day of design flow over 1000 gallons per
day as specified in the table,unless it can be demonstrated by an RPE or geologist that a
mechanical or natural barrier will prevent contamination
If a Colorado RPE chooses to exercise this option he/she shall use language such as appears below.
Based on geological conditions and/or engineering controls and evaluation of risk of contamination
of surface water and ground water,it is not necessary to add 8 feet additional distance for each 100
gallons of wastewater per day of design flow over 1,000 gallons per day as specified in the table to
prevent contamination. The foot separation between the proposed absorption area and
surface water or ground water is appropriate to prevent contamination.
If the ground has been cut into,such as with a road cut,cut bank,fill area,or irrigation ditch,its closest edge
must be at least four times farther away than its height from the closest edge of the leach field or any part of
an ISDS system if the system discharges effluent into or onto the surrounding soil. This requirement can be
waived if it can be demonstrated by an RPE or a geologist that a mechanical or natural barrier will prevent
lateral effluent surfacing.(See diagram below.)
�-► 4h .----+I
0
h Absorption Trench or Seepage Bed
An absorption field may be installed in an easement provided there is clear language addressing the
permanent nature of the installation,and a thorough agreement between all parties that the
easement is for an absorption field only. The easement must be isolated and protected from all other
development(including,for example,being used for parking,driveway,storage,or large animal
confinement area).
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26
ARTICLE 8: Tank Design Requirements
8-1 Septic Tank Design Criteria
8-2 Tank Size:A septic tank's capacity or volume must be based upon the number of rooms likely to be
used as bedrooms during the life of the building,according to the following formula.
Design Flow=number of bedrooms x 2 persons per bedroom x gallons/person/day x
1.75(peaking factor).
Design Flow x 1.25(30 hour retention time)=Volume
Gallons/person/day will vary depending upon living area of the home:
0-2000 square feet of living area,use 75 g/p/d.
>2000-6000 square feet of living area,use 100 g/p/d.
over 6000 square feet of living area,use 130 g/p/d.
8-3 Septic Tank Design Criteria:
83.1 The tank capacity must be at least 750 gallons.However,gray water systems may have tanks smaller
than 750 gallons. A septic tank must still provide a minimum of 30 hours detention time.
83.2 The inlet must be at least 3 inches higher than the outlet. An inlet Tee or baffle must extend above the
surface of the liquid to within 1 inch of the bottom of the tank top and must extend at least 14 inches below
the inlet.
8-3.3 A filter is required on the final outlet bee or at some point between the septic tank and the absorption
field so that only liquid effluent will be discharged. Other outlet tees or baffles must extend above the
surface of the liquid to within one inch of the underside of the tank top. Tees must extend at least 14 inches
below the outlet
8-3.4 The distance from the outlet to the underside of the tank top must be at least 10 inches.
8-3.5 Liquid depth must be at least 30 inches and must not exceed the tank length or 60 inches,whichever is
less.
83.6 A septic tank must have two or more compartments(or more than one tank in series to provide the
necessary capacity). The first compartment must be at least as large as the second compartment.
8-3.7 The transfer of liquid from the first compartment to the second or successive compartment must be
made at a liquid depth of at least 14 inches below the outlet invert,but not in the sludge zone.
83.8 At least one access no less than 20 inches across must be provided in each compartment of a tank.
83.9 The opening cover of a septic tank,inspection port,or sampling access port must be marked and must
be no more than 8 inches below the finished grade. It must be made of materials resistant to degradation
from moisture or sewer gases.
83.10 Pipe meeting or exceeding ASTM standard 3034 properly supported to prevent failure by settling
must extend from the septic tank at least five(5)feet from the inlet and outlet ends.
27
8-3.11 Septic Tank Materials:concrete tanks shall meet minimum standards as established by Colorado
Department of public Health and Environment. Other materials such as fiberglass or plastic which result in
an adequate and durable construction and which resist excessive corrosion or decay may be approved. Steel
and other metal septic tanks are prohibited.
84 Aerobic Sewage Treatment System:
General Design: Aerated sewage treatment systems must have a seal of approval from the National
Sanitation Foundation or an equivalent testing program,and systems using aerated treatment systems must
be designed by an RPE. Its aeration compartment,its inlet and outlet arrangements,baffling and air
application must.
8-4.1 Allow for intimate mixing of applied sewage,return solids,and applied air.
8-4.2 Prevent excessive short-circuiting of flow.
8-4.3 Prevent the deposition and buildup of solids in the aeration compartment.
8-5 Method of Aeration: The method of aeration must be by mechanical aeration,diffused air,or a
combination of these. It must at all times maintain aerobic conditions at the maximum organic loading in
both the aeration and settling compartments.
28
Article 9: Inspection and Maintenance
9-1 Responsibility The owner and the party in possession of real property on which an LSDS is used,must
be jointly and severally responsible for operation and maintenance of the system unless jurisdiction for
responsibility has been transferred to a public,quasi-public,or political subdivision.
9-2 Service Iabek•For treatment plants using mechanical apparatus or under a service policy,a clearly
visible,permanently attached label or plate giving instructions for obtaining service must be placed at a
conspicuous location.
9-3 Maintenance and Cleaning:The Department may require the owner or user of a system to maintain and
clean an ISDS. If the Department deems it necessary,the Department must be notified on completion of the
work and provided with evidence of the nature of the work.
Maintenance and cleaning of systems to insure proper functioning,shall occur with the following frequency,
at a minimum:
Type of Component InspectiorVMaintenance Cleaned or Pumped
septic tanks every 2 years every 2 years
vaults,privies every 4 years as necessary
aeration plants every 6 months every year
filter trenches every 6 months every 8 years
absorption beds every 6 months every 8 years
ET beds eve 3 months eve 8 ears
um s,pumping chambers eve 6 months eve 4 ears
The Department may require proof of proper maintenance and cleaning,pursuant to any such schedules and
practices. The owner of the system must submit this proof periodically to the Department.
9-4 Monitoring and Sampling:The Department may require reasonable periodic collection and testing by
the owner of effluent samples from ISDSs for which monitoring of effluent is necessary in order to insure
compliance with the provisions of these rules and regulations. Monitoring must be performed not more than
two times a year,except when required by the Environmental Health Specialist in conjunction with an
enforcement action.
9-4.1 Any owner or occupant of property on which there is an ISDS may request the Department's assistance
in analyzing effluent samples from the system.
94.2 The Department may perform such collection and testing services.If the Department collects and tests
effluent samples,a fee not to exceed that which is allowed by 25-10-101 et seq.(as amended)C.R.S.1973,
may be charged for each sample collected and tested. Payment of such charge may be stated in the permit as
a condition for its continued use.
9•5 Disposal of Waste Materials:Disposal of waste materials removed from a system in the process of
maintenance or cleaning must be accomplished at a site approved by the Department in a manner that does
not create a hazard to the public health,a nuisance or an undue risk of pollution and that complies with state
and local rules and regulations. (See Sludge Regulations and Solid Waste Regulations.)
29
9-6 No Discharge is Permitted That Does not Comply With Rules and Regulations:No sewage or effluent
may be discharged into or on the surface of the ground or into state waters unless the sewage system and
effluent meets the minimum requirements of this regulation and the owner or applicant has obtained the
proper discharge permits from the Division.
9-7 Termination of Use of System:The contents of a septic tank,vault,or seepage pit,the use of which has
been terminated,must be properly disposed of. Then the emptied tank,vault,or pit must be filled with soil
or rock,or the Environmental Health Specialist may require the tank or vault to be removed and disposed of
properly.
30
Article 10: Component Design Criteria
10-1 Design Features(General)
10-1.1 Reliability:Each component of an ISDS must function in a way not adversely affected by normal
operating conditions including erosion,vibration,shock,climatic conditions,and usual household chemicals
used. Design shall be such as to exclude flies and rodents and to prevent the creation of nuisances and public
health hazards and shall provide for efficient operation and maintenance.
10-1.2 Pipe Standards: All wastewater lines used in ISDSs must be constructed of compatible pipe,bonding
agent,and fittings. The following may be used:plastic pipe and fittings with a nummum wall thickness of
ASTM Standard 3034,SDR35,or equivalent;perforated distribution pipe surrounded by rock within a soil
absorption system with a minimum wall thickness conforming to ASfM Standard 2729;or corrugated
polyethylene pipe with smooth interior meeting ASTM F405 and AASHTO M252 specifications or
equivalent. Tile,open-joint pipe,and cast iron pipe may not be used in ISDSs.
10-1.3 Codes: All components,work,equipment and material must be designed,operated and maintained
so as to comply with the minimum requirements of the applicable and current Plumbing,Electrical,Building
or other code in force on the date of the ISDS Permit Application.
10-1.4 Identification:Major components not constructed on the site where installed must have a permanent
plate or other indelible marking,easily read and visible,for the purpose of inspection,to include name of
manufacturer,model or serial number designation,and maximum design capacity of the unit.
10-1.5 Structural Integrity: Tanks,treatment units,and piping material must be watertight and must be
certified by the Division. Under certain circumstances,the Department may require the tank be filled with
water prior to backfill to check for leaks.
10-1.6 Tank Anchoring:Where groundwater may cause instability problems to the septic tank,pumping
chamber,vault,or other tanks in the ISDS due to flotation,the tank shall be anchored in a manner designed
and approved by a Colorado Registered Professional Engineer.
10.1.7 Accessibility for Inspection and Maintenance: Each septic tank,aerated treatment plant,or pumping
chamber must have an access port to permit periodic inspection,collection and testing of samples and
maintenance of all components and compartments. These include submerged bearings,moving parts,tubes,
intakes,slots,filters,inlet and outlet baffles,and other devices. Access ports must terminate within 8 inches
of the finished grade and must be marked.
10.1.8 Indicators of failure for systems using mechanical apparatus: A signal device must be installed,
inside the dwelling if possible,that will provide a visual and audible warning to the user that the system or
component is not operating properly.
10-1.9 Serviceability: Components must be designed and constructed so that when installed according to
manufacturer's recommendations,they can be easily maintained,sampled,drained,pumped,inspected and
cleaned. Pumps must be able to be removed without entering the pumping chamber.Electrical boxes must
be installed outside the pumping chamber.
10-1.10 Instruction manuals: The manufacturer must provide clear,concise instructions covering the unit
that,when followed,will assure proper installation and safe and satisfactory operation.
31
10-1.11 Restricting activity over system: The ground over any part of the ISDS must be restricted to activity
or use that will allow the system to function as designed and that will not contribute to compaction of the soil
or to structural loading detrimental to the capability of the component to function as designed.Driveways,
parking areas,storage buildings,large animal confinement areas and other similar uses may not be placed on
or above an ISDS disposal field;although properly engineered seepage pits and drywells are allowed in these
areas for failed or remodeled systems.
10-1.12 Distribution box Distribution boxes are recommended. They must be of adequate size,large
enough to accommodate and equally distribute effluent to the lateral lines. They must be constructed with
the inlet hole at least one(1)inch above the level of the outlet hole. A permanently installed baffle plate or
comparable approved device must be installed at the inlet to slow liquid entering the box enough to stabilize
the effluent before entering the absorption field. The distribution box must be filled with water to check the
level and check for leaks at the time of inspection,prior to back filling.
10-1.13 Sewage pumping system where applicable:
a. The non-clog pump(grinder pump)opening shall have at least 2-inch diameter solids
handling capacity where raw sewage is pumped or not more than 1/2-inch diameter solids
handling capacity if previously settled effluent is pumped.
b. Automatic liquid level controls must be provided to start and shut off pumps at a frequency
required by the design.
c. The pressure pipe shall be of sufficient strength to accommodate pump discharge pressure
and the pipe shall be sized to maintain a velocity of 2 or more feet per second.
d. Automatic air release valves(if used)must be installed at high points in the pressure line
where necessary to prevent air locking.
e. A storage basin preceding the pump must be provided to allow pump cycling commensurate
with the pump design capacity. The second compartment of the septic tank may not be used
as a pumping chamber,unless it can be shown that a minimum 30-hour detention time will not be
decreased and the pump is screened or provided with an approved filtering device to assure that
only liquid effluent will be discharged.
f. The discharge line from the pumping chamber must be protected from freezing by burying
the pipe below frost level or sloping the pipe to allow it to be self draining.
10-1.14 Floodplains: No new or expanded system may be installed in a floodway or floodplain.A repair
system in such areas shall minimize or eliminate infiltration of floodwaters into the system,and discharge of
the system into the floodwaters.
10-1.15 Deflection of runoff-The ground surface must be graded to deflect precipitation or other outside
water from the disposal area. The absorption area must be protected against erosion.
10-1.16 Non watertight components:Components that are not watertight should not extend into areas of the
root system of nearby trees.
10-1.17 Cesspools prohibited:Construction of cesspools is prohibited.
32
10-1.18 Blasting:Blasting(such as:pneumatic,hydraulic,explosive)to create an absorption area or to
increase permeability is prohibited.
10.2 Installation
10-2.1 General: All tanks,chambers,vaults,distribution boxes and similar devices must beset on a firm and
level base except where anchored.
Cleanouts shall be installed so that they open to allow cleaning in the direction of flow of the waste.
Cleanouts shall be installed no further than 100 linear feet apart,or at every change of direction greater
than forty-five(45)degrees.
The building sewer and effluent line shall be laid with a minimum fall of one-eighth inch per foot
(1/8"/ft.). The sewer and effluent lines shall be constructed of solid wall watertight pipe to the
absorption area or distribution box.
10-2.2 Mechanical components:Pumps,dosing tanks,packaged plants,and similar devices must be
installed in a properly vented location. All vents,air intakes,and air hoses must be protected from snow,ice,
or water vapor accumulations.
Mechanical components must be protected against damage or impairment of their efficiency by flooding,
foaming,backflowing,or receiving too much flow.
10-2.3 Covers,barriers,or other protection: Ail systems must have protection of openings against entrance
of insects and rodents.
10-3 Optional design features
10-3.1 Alternating systems: A diversion valve or other approved diversion mechanism may be installed on
the septic tank effluent line allowing alternating soil absorption systems to improve the performance of the
system. The diversion mechanism must be readily accessible from the finished grade. Reductions in
absorption field area are not applicable to alternating systems.
10-3.2 Dosing:where dosing is used in conjunction with soil absorption systems,the dosing frequency
should be the following:
Soil Texture Dosing Frequency
Sand 4 doses/da
Sandy Loam 1 dose/da
Loam Frequency not critical*
Silty Loam 1 dose/da *
Silty Clay Loam 1 dose/da *
Clay Frequency not critical*
*Long term resting provided by alternating fields is recommended
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34
Article 11: Design Requirements for
Conventional Systems
11-1 Absorption Area Size Calculations: For a system treating and disposing of effluent through a soil
absorption system,the method for calculating minimum absorption area must be based on the capacity of the
soil to absorb liquids,and must comply with the requirements of this regulation. This is established by the
percolation test.
The minimum absorption area in square feet(A)for an ISDS is a function of the design flow of sewage in
gallons per day,(Q),and the percolation rate in minutes per inch,(t),according to the formula:
A =Qx ft-
5
where Q=#of bedrooms X 2 people/bedroom X gpd/person X 1.75
11-2 Reductions in Size of System: Reductions in system size may be allowed in the following cases.The
Department may require review by an RFE of requested size reductions.The maximum total reduction
allowed from all combined alternatives is 30%for beds and 50%for trenches which is allowed only if lot and
soil conditions are optimal.
11-2.1 Deep gravel:For additional gravel in excess of six(6)inches below the bottom of the distribution pipe,
a maximum 30% reduction may be allowed in a bed design and a maximum 50%for a trench design at the
discretion of the Environmental Health Specialist if the lot is large and conditions are optimal.The reduction
in size should be calculated as follows:
L=length required prior to adjustment X +2
(W+1+2d)
where W=width of trench or bed in feet
d =depth of gravel below distribution pipe in feet
11-2.2 Gravelless/chambered systems:Reduction in area may be allowed with approval of the Division and
at the discretion of the Environmental Health Specialist,with a maximum 30% reduction in a bed design and
a maximum 50%for a trench design if lot and soil conditions are optimal. No reduction can be taken for soils
with a perc rate slower than 60 mpi.
11-2.3 Dosing may not be used to provide system size reductions.
11-3 System Size Increases:Increases in required system size will be made if fixtures that cause unusually
high water use are installed.
11-4 Construction/Design Requirements for Conventional Systems
11-4.1 Gravelless soil absorption or chambered systems: All types of gravelless soil absorption systems
must be approved by the Division and installed according to the manufacturer's design.
35
11-4.2 Drywells: Dry wells may be permitted only in soils with a percolation rate faster than sixty(60)
minutes per inch. They must meet the following requirements.
a. Dry wells must be filled with clean,graded rock that may vary from 1/2 to 2 1/2 inches in
diameter. The rock must extend from the bottom of the pit to at least two(2)inches above the
inlet pipe.
b. At least one four(4)inch perforated vertical stand pipe must be attached to the end of the
distribution line with a tee fitting. It must go to the bottom of the drywell and up to the
finished grade and be fitted with a removable cap to be used as an inspection pipe.
c. The absorption area of the dry well must be computed on the basis of percolation rates of
each stratum penetrated. Soil logs must be provided showing percolation rates in each layer.
The weighted average of the results must be used to obtain a design value.
d. The effective area of the drywell will be calculated by adding the area of the sidewalls below
the horizontal inlet line and the area of the bottom of the pit,excluding any impermeable
layer penetrated.
e. Drywells must be separated by a distance equal to the depth of the excavation or ben(10)feet,
whichever is greater.
11-4.3 Seepage pits:These may be permitted by the Department as an alternative where the subsurface
conditions are otherwise suitable for pit installations. Percolation rates must be 30 minutes per inch or faster.
The following requirements must be met.
a. The capacity of the pit must be computed on the basis of percolation bests made in each
stratum penetrated. A soil log is required showing percolation test results in each strata. The
weighted average of the results must be used to obtain a design figure. Soil strata in which the
percolation is slower than 30 minutes per inch must not be used for absorption or seepage.
b. The effective area of the pit is the vertical wall area(based on dug perimeter)of the RMELous
strata below the inlet. No allowance may be made for impervious layers or bottom area.
Usable square footage of the pit will be calculated from the inlet pipe to the bottom of the pit.
c. Pits must be 3 times farther apart than the diameter(or length)of the biggest pit For pits over
20 feet deep,they must be at least 20 ft.apart
d. Pits must have both vertical sidewall and top supporting structural concrete or other material
of equal structural integrity.
11-4.4 Pipe and Gravel Absorption trenches and seepage beds:
a. The bottom of the trench or bed and distribution lines must be level.
b. Perforated distribution pipe must extend the whole length of the trench or bed.Inspection
pipes shall appear at the ends of the trenches or absorption bed.
c. Pipe must be surrounded by the cleanest available graded gravel,rock or material of equal
efficiency that may range in size from 1/2 inch to 21/2 inches.
36
d. There must be gravel from at least 2 inches above the top of the
distribution pipe to at least 6 inches below the bottom of the distribution pipe.
e. The distance between trenches and between adjacent fields must be at least six(6)feet
sidewall-to-sidewall.
f. The distance between distribution lines in a seepage bed must not be more than 6 feet.
g. There must be a distribution line within 3 feet of each sidewall of the seepage bed.
h. Pipe for gravity distribution must be no less than 4 inches in diameter and may not extend for
more than 100 feet.
i. It is recommended that the ends of lines be hooked together or air vented;all other ends must
be capped.
j. The top of the gravel or other material used must be covered with a layer of hay,straw or
similar pervious material to a depth of at least 2 inches. Pervious fabric barriers are also
permitted. An impervious covering may not be used.
k. Tile or open joint pipe must not be used.
1. A final 10 inch or more cover of soil suitable for vegetation must be placed from the top of the
hay,straw or similar material to the finished surface of an absorption trench or seepage bed.
The final cover must be graded to deflect runoff water away from the disposal area.
in. Machine tamping,rolling or hydraulic compaction of final cover must not be permitted,
however,hand tamping may be allowed where necessary to stabilize the soil to prevent
erosion or the intrusion of extraneous water.
n. If dosing is used,the dosing chamber must be sized to account for the volume of the
distribution system and the dosing frequency.
114.5 Serial distribution system: A serial distribution system is used everywhere it is too steep to install a
single level absorption field,unless a distribution box or dosing chamber is used.They must meet the
following requirements.
a. The bottom of each absorption field and its distribution line must be level.
b. There must be a minimum of 10 inches of ground cover over the gravel fill.
c. An absorption field must follow approximately the ground surface contours so variation in
absorption field depth will be minimized.
d. There must be a minimum of 6 feet(horizontal measurement)of undisturbed earth between
adjacent absorption field trenches and between the septic tank or other treatment unit and
the nearest absorption field.
e. Adjacent absorption fields must be connected with a relief line or a drop box arrangement
such that each trench fills with effluent to the top of the gravel before flowing to succeeding
trenches.
37
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38
Article 12: Design Requirements for ISDS
12-1 General:All systems require department approval and permitting. The Department may require
additional site-specific information in cases where conflicting or inconsistent information is present. Such
review would assess the appropriateness of the design,and not whether alternative designs may exist.
12-2 Area Size Calculations for Engineer Designed Systems:
Either of the following formulas may be used to determine the size of an engineered system:
12-2.1 The minimum absorption area in square feet(A)is a function of the design flow of sewage in gallons
per day,(Q),and the percolation rate in minutes per inch,(t),according to the formula:
A = Qx,rt-
5
where Q=2 X#of bedrooms X gpd X 1.75.
Note: Where the percolation rate is found to be faster than five minutes per inch in soils of sandy texture,the
minimum value of the"t"for use in this formula must not be less than 5".
12-2.2 Long Term Acceptance Rates(LTAR): The minimum absorption area A in square feet may be
computed as a function of the design flow(Q)and the Long Tenn Acceptance Rate(LTAR)according to the
formula:
A =-A-
LTAR
Maximum loading rates of effluent volume for soil absorption s stems in native soils are as follows:
Percolation Rate Soil class Typical Soil Textures Maximum Loading Rate
minutes inch (Appendix 4 al .ft. da
0-10 I Sand 1.30
11-20 II Sandy Loam to Loam .72
21-30 lII Loam .50
31-40 IV Loam to Silty Loam .40
41-60 V Cla Loam .30
Over 60 VI Cla 1 .20
39
12-3 Construction/Design Requirements for Engineer-designed systems
Miscellaneous:
12-3.1 Sampling access: Where a required final effluent sample cannot be easily obtained,a sampling well
must be constructed. The sampling well shall be accessible and provided with a properly secured cover.
12-3.2 Soil building:Soil building or replacement will be permitted to bring the soil within the requirements
of suitable soil if part of an engineered design.
12-4 Mound Systems: A mound system is a soil absorption system in which the top of the effluent
distribution pipe is installed above the original grade of the area used for absorption,and is typically used in
areas where groundwater or bedrock are close to the surface. Mound systems must be designed by a
Colorado RPE. The design must be site-specific and include specifications for fill material,area size
calculations and design,distribution networks,cap,topsoil,final grading,and other information pertinent to
the construction of the system as may be requested by the Environmental Health Specialist
12-4.1 The distribution system must be designed for uniform effluent application throughout the mound.
12-4.2 The distribution system must be graded to drain back to the dosing chamber or buried below frost
line.
12-4.3 The final slope of the mound backfill must be no greater than 3 to 1(three[31 feet horizontally to one
[1]foot vertically).
12-4.4 The mound must be planted with suitable vegetative cover.
125 Sand Filter Systems:Sand filter systems must be designed by a Colorado RPE and meet the following
requirements.
12-5.1 The filtering material shall be clean,course sand,all passing a screen having four meshes to the inch
(#4 sieve size). The sand shall have an effective size between 0.25 and 0.6 mm. The uniformity coefficient
shall be 4.0 or less.
12-5.2 The sand must be at least 2 feet deep below the distribution lines. Distributors and underdrain are
required and be surrounded by coarse screened gravel or crushed stone.
12-5.3 Underdrain effluent must then be discharged via a soil absorption system or be further treated as
necessary to meet receiving water standards or those of Article 1X as applicable.
12-5.4 All of the gravel or stone must pass a 21/2 inch screen and must be retained on a 3/4 inch screen.
Fine gravel 1/4 inch size or less may be used above and around the coarse material,both at the distributor
and underdrains.
12-5.5 The separating distance between parallel distribution lines must be less than 6 feet,and a distribution
line must be located within 3 feet of each filter sidewall.
12-5.6 Pipe for gravity distribution must be no less than 4 inches in diameter. The distributor and
underdrains may be of agricultural tile,or bell and spigot pipe,or perforated pipe.
40
12-5.7 The slope of the distributors must be 0.4 percent where dosing tanks are not used,and the slope of the
underdrains 0.5 to 1.0 percent.
12-5.8 The sand must be thoroughly settled by flooding or other means before the distributors are placed at
the final grade.
12-5.9 The bop of the sand bed must be no less than 4 feet above the high ground water table for installations
in which effluent percolates downward through the soil.
12-5.10 The minimum area for a sand filter must be computed as a function of the maximum daily sewage
flow. An application rate of 0.95 gallons per square foot per day shall be used.
12-5.11 A dosing tank must be provided where the total filter area exceeds 1,800 square feet The size of the
dose,or the net capacity of the dosing tank,must be at least 75 percent of the volume of the distributors.
12-6 Evapotranspiration(0)Disposal Systems: An Er system may be used exclusively or in combination
with a soil absorption system and must meet the following requirements.
12-6.1 An ET system must be designed by an RPE who must furnish design data for a complete review and
approval of the design by the Department and issuance of a permit
12-6.2 Data to be furnished to the Department must include,but is not limited to: liner material(that must
comply with at least the minimum standards of this regulation)bedding,properties of the soil in the Er bed,
site-specific climate and snow cover data,evaporation rates,and type of vegetation cover.
12-6.3 When high groundwater table,bedrock,fractured rock,or highly pervious material(percolation faster
than 5 minutes per 1 inch)endanger the underground water,a durable and impermeable liner must be
installed to keep sewage effluent from entering the underlying formation or groundwater table. The liner
must be a watertight membrane of at least 0.01 inch(10 mil)thickness and must be polyvinyl chloride or
material of equal or greater integrity.
12-6.4 An Er system must be located in an area where there is exposure to sunshine enough days per year
and hours per day to allow for adequate functioning of the system,and must take into account the number of
months per year in which the area is covered with snow. Er systems may not be used in shaded north-facing
areas in valleys,for example,but must be in areas that are open to sunshine and exposed to sufficient
breezes.
12-6.5 The system bed must be crowned and covered with a minimum of four(4)inches of selected backfill
material and with a vegetation cover.
12-6.6 The bed area must be protected to prevent vehicular travel and to prevent damage from pedestrian
travel The ground surface must be graded to deflect precipitation and other outside water away from the
disposal area.
12-6.7 The design must provide enough wicks(sand structures that penetrate through the rock media to the
bottom of the bed)so that their total base area is equal to 10 to 15 percent of the bed surface area. The wicks
must be uniformly spaced throughout the bed.
12-6.8 The system must be large enough to evaporate/transpire an entire year's flows during the time the
system is working,using local net lake evaporation rate. (If the system is designed as a
41
percolation/evapotranspiration system,the amount of storage and ET capacities may be reduced by the
volume of effluent percolating into the soil.)
12-6.9 Sand used in ET or Evapotranspiration/Absorption beds for cover must meet the following gradation
requirements and be approved by the design engineer:
Gradation Requirements for Sand Used in ET Beds
Sieve Size Percent % Passing
4 100
40 50-55
200 <15
Note: Except for dwellings,if the system is designed for summer use only,as determined by the
Department,multiply the above area by 0.6 to obtain the required area.
12-6.10 The following formula may be used as a guide for determining the area necessary for total ET of
septic tank effluent:
Area(in square feet)=Design Flow(in gallons per day)x 586
Lake Evaporation Rate at the Site (inches/year)
12-6.11 As an alternative,a system may be designed on the basis of a monthly water balance for the system.
Such a design must provide for enough storage for average daily flows for all periods in which
evapotranspiration is not expected to occur. The procedure for designing a system using this method is to
calculate the following:
a. Design flow on a monthly basis,
b. ET rates on a monthly basis,based on local conditions,
c. Monthly precipitation data,using the worst-case data for each month over a 10-year period using
data from the City of Aspen Water Department unless it can be shown that more accurate site-
specific data exists,including monthly snow melt into the bed,
d. Monthly calculated flow out of the bed,
e. Cumulative storage in the bed.
Tables of the above information for the site must be provided to the Department along with other system
data.
12-7 Wastewater Ponds:A wastewater pond must be designed by a Colorado RPE.It may be used
following the septic tank at the discretion of the Department,and must meet the following criteria.
12-7.1 The pond must be designed for a loading not to exceed 0.46 pounds of BOD5 per 1,000 square feet of
water surface area. Size must be determined by expected loading and local evaporation rate. Aeration may
be required at the discretion of the Department to improve treatment.
12-7.2 Maximum water depth in the pond must not be more than 5 feet The inside slope of the pond,dike
or embankment must not be steeper than 2:1,(2 feet measured horizontally for each foot measured
vertically). A center inlet must be provided.
42
12-7.3 Unless four feet of impervious soil exists beneath the bottom of the pond,said pond must be
constructed in impervious soil or be sealed to prevent excess seepage of wastewater.
12-7.4 Adequate safety protection must be provided,such as fencing and signs,to protect against personal
injury.
12-7.5 Surface runoff must be diverted away from the pond except where the pond is designed to be large
enough to accommodate runoff.
12-8 Constructed Wetland Treatment A constructed wetland treatment system,if approved by the
Department on a site-specific basis,must be designed by a Colorado RPE with experience in wetland system
design. The design must be site specific and include specifications for loading,capacity,liner material(The
liner must be a watertight membrane of at least 0.01 inch(10 mil)thickness and must be polyvinyl chloride or
material of equal or greater integrity.),filter media,density and species of plant material,effluent level,final
discharge type,and other pertinent information requested by the Environmental Health Specialist. Wetlands
systems should be installed only in situations where there will be consistent flows. The design must include
estimates of effluent quality at the inlet and outlet. Sampling ports are required.Sampling is to be conducted
by the owner.The following requirements also apply.
12-8.1 The lot must be big enough to accommodate a traditional ISDS so that if the constructed wetlands
system fails and cannot be repaired,the owner will have room on which to construct a replacement system.
12-8.2 The system must be designed using the"plug flow model"or comparable standard that allows
adjustment in design for different temperature conditions that could be a factor in Pitkin County.
12-8.3 There must be no discharge of effluent off the property unless the applicant has obtained a National
Pollution Elimination Discharge System permit from the Division. If such a permit is obtained,the applicant
must monitor treatment system effluent prior to discharge to receiving waters of the state,using sampling
parameters of the Division s guidelines.
12-8.4 No permit may be issued if the Department determines a health hazard will be created,or a private or
public nuisance will result,or that undue risk of contamination exists.
12-8.5 The applicant must notify immediate neighbors,or the homeowners'association if the property is
regulated by covenants,and allow them 30 days from the date of application to the Department,to review
and comment on the installation. Comments must be provided to the Department for consideration before
the permit is issued.
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44
Article 13: Design Requirements for Other
Facilities
13-1 Gray Water Systems: A gray water system is a system designed to collect,treat and dispose only liquid
wastes from sinks,tubs,showers and laundry or other approved plumbing fixtures,but not including toilets.
Gray water systems must meet all minimum design and construction standards for a septic tank system
based on the amount and character of wastes for the fixtures and the number of persons to be served.
Minimum tank size is determined by the formula(#of gpd-24.8 gpd for sewage)x 2 people/bedroom x
#of bedrooms x 30 hours(1.25 days). Minimum field size is determined by the formula in these regulations
with the flow being the design flow without toilet(black water)wastes.
13-2 Vaults:A vault must have a minimum 1000-gallon capacity and meet the same installation and
construction standards as septic tanks. Vaults may be permitted under limited use occupancy for sewage
disposal on property that cannot accommodate a septic system. An audible and visual signal device must be
installed to indicate when pumping is necessary.
13-3 Vault Privy: A vault privy must include fly-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 super-structure base,a floor and riser of concrete or other impervious material,and hinged seats and
covers of easily cleanable,impervious material. All venting must be fly-proofed with No.16 or tighter mesh
screening. Capacity of the vault privy must be no less than 400 gallons.
13-4 Incineration and Chemical Toilets: An incineration toilet,that may be used in connection with a gray
water system by permit from the Department,must be designed and installed in accordance with all
applicable federal,state,and local air-pollution requirements. A portable chemical toilet,that may be used
by permit from the Department,must have a superstructure that meets the requirements of the paragraph
titled Vault Priw. Use of a portable chemical toilet in permanently occupied buildings is prohibited except
during construction or under emergency circumstances as determined by the Department. Chemical toilets
must be provided at construction sites when approved toilet facilities are not available.
13-5 Business,Commercial,Industrial,Institutional or Multi-family Dwelling Waste Systems:
13-5.1 Performance criteria and construction standards for a system that will service commercial,business,
institutional or industrial property,or multifamily dwellings(any dwellings consisting or four or more units,
such as a fourplex or larger or four or more individual units on one system)must conform to these
guidelines.
13-5.2 Such systems must be designed by an RPE and approved by the Department,unless the wastes are
not exclusively domestic type wastes,in which case review must also be by the local Board of Health.
13-6 Composting Toilets: Composting toilets must bear the seal of approval of the National Sanitation
Foundation or an equivalent testing program.Composting toilets must be operated according to
manufacturer's specifications.
13-6.1 Composting toilets may be used for sewage and readily decomposable household garbage that is not
diluted with water or other fluids. The volume of the toilet must be sufficient to accommodate the number of
persons served,according to the manufacturer's specifications.
13-6.2 Compartment and appurtenances related to the unit must include fly-tight construction and exterior
ventilation as required by the plumbing code.
45
13-6.3 Composting toilets must be emptied according to the manufacturer's practices and county
regulations.
13-6.4 If a system will be installed where low temperature may be a factor,design must compensate for the
effects of the low temperature.
13-7 Recycling Systems that Recycle Treated Waste Water. Systems that recycle treated wastewater for
non-drinking purposes such as flushing toilets or urinals:
13-7.1 That portion of the wastewater recycled for non-drinking purposes such as flushing toilets or urinals
must meet the treatment requirements of Appendix 1 of these regulations for effluent in which the possibility
exists for occasional direct human contact.
13-7.2 No cross-connection to a pipe,fixture,or supply containing potable water is permitted.
13-7.3 No system may be permitted that will recycle wastewater for drinking purposes except a system
that must consistently meet all of the sanitation and maximum contaminant level requirements of rules,
regulations and standards of the Colorado Department of public Health and Environment and of the local
Board of Health.
13-8 Manufactured Units Using Mechanical Apparatus for Treatment of Sewage:Systems using
mechanical parts may not be used if a system can be designed without use of mechanical components.No
unit using mechanical apparatus may be used if its failure would cause discharge either upon the ground or
beneath the ground surface or that might adversely affect state waters unless:
13-8.1 The system is installed within a geographic area where a public,quasi-public,or private entity,or
political subdivision,such as a homeowners association is continually responsible for the efficient operation
and maintenance of said unit,
13-8.2 Or the operator of the system insures an efficient operation of all mechanical and electrical component
parts provided prior to and during continuing use and provides annual maintenance reports to the
Department.
13.9 Experimental Systems
13-9.1 For purposes of this Section,a system employing new technology is a system based on improvements
and developments in technology of sewage disposal and not otherwise provided for in this regulation.
13-9.2 Certification:
Upon notice of certification by the Division,an Environmental Health Specialist may consider a permit
application for the certified system in the same way as applications for systems that treat and dispose of
effluent through an absorption system.
The local Board of Health may determine whether to issue a permit for an experimental system that has not
been certified.
13-9.3 The lot must be big enough to accommodate a traditional ISDS so that if the experimental system
fails and cannot be repaired,the owner will have room on which to construct a replacement system.
46
Appendix 1
Systems Not Using Soil Absorption or Sand Filter,
and Non-discharging Systems
1.0 General: Systems that will discharge effluent directly to the atmosphere,the ground surface or below
ground,or that employ aerobic principles of sewage treatment or a dispersal system,may be permitted only
if designed by a registered professional engineer. This Appendix 1 does not apply to systems discharging
below ground through a soil absorption system or sand filter system or to a non-discharging system.
1.1 Review of Application: The local Board of Health must review all applications for such systems that
may result in discharge or drainage of effluent from the property of origin. No permit may be issued for
such a system if the local Board of Health determines a potential health hazard or private or public nuisance
or undue risk of contamination exists. The Department may review applications and issue permits for
systems that do not permit the drainage of effluent off the property of origin. For systems discharging to
State waters,see Appendix 2.
1.2 The following minimum performance criteria are required for all systems pursuant to this Appendix 1:
1.2.1 If effluent discharge is made into the atmosphere or upon the ground surface in areas in which the
possibility exists for occasional direct human contact with the effluent discharge,the effluent at the point of
sampling must meet each of the following standards:
a. The geometric mean of the fecal coliform density must not exceed twenty five(25)per one
hundred(100)milliliters when averaged over any five(5)consecutive samples,and no single
sample for fecal coliform may exceed two hundred(200)per one hundred(100)
milliliters.
b. The arithmetic mean of the standard 5-day biochemical oxygen demand(BOD5)must not
exceed twenty(20)milligrams per liter when averaged over any three(3)consecutive
samples.
c. The arithmetic mean of the total suspended solids must not exceed forty(40)milligrams per
liter when averaged over any three(3)consecutive samples.
1.2.2 If the effluent discharge is made into the atmosphere or upon the ground surface in an area so restricted
as to protect against the likelihood of direct human contact with the discharged effluent,the effluent at the
point of sampling must meet each of the following standards:
a. The geometric mean of the fecal coliform density must not exceed five hundred(500)per one
hundred(100)milliliters when averaged over any five(5)consecutive samples,and no single
sample may exceed five thousand(5000)fecal coliform per one hundred(100)
milliliters.
b. The arithmetic mean of the standard 5-day biochemical oxygen demand(BOD5)must not
exceed twenty(20)milligrams per liter when averaged over any three(3)consecutive
samples.
c. The arithmetic mean of the total suspended solids may not exceed forty(40)milligrams per
liter when averaged over any three(3) consecutive samples.
47
1.2.3 If effluent discharge is made beneath the surface of the ground and discharge will not be made through
suitable soil,either existing or constructed,or through a sand filter,the system must be designed by a
registered professional engineer and the following standard must be met:
a. There must be at least(4)feet of soil between the maximum seasonal high water table and the
level of effluent discharge.
b. The arithmetic mean of the standard 5-day biochemical oxygen demand(BODs)must not
exceed sixty(60)milligrams per liter when averaged over any three(3)consecutive samples.
c. The arithmetic mean of the total suspended solids must not exceed one hundred(100)
milligrams per liter when averaged over any three(3)consecutive samples.
1.2.4 To determine compliance with the standards contained in this Appendix 1,the owner must take
samples at least once per week.
1.3 Methods of Analysis-Sampling Points:All effluent samples must be analyzed according to the
methods prescribed in the current edition of"Standard Methods for the Examination of Water and
Wastewater"(American Public Health Association). The point of sampling must be a location that is
representative of final discharge from the system.
48
Appendix 2
Effluent Discharged to State Waters
Any system that will dispose of effluent by discharging into State waters must be designed by an RPE,and
the application must be submitted to the Department and forwarded to the Division for issuance of a permit
in compliance with all applicable regulations of the Colorado Water Quality Control Commission. After
permitting by the Division,the application with attached state permit must be given to the Department for
final approval.
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50
Appendix 3
Appeals and Penalties
3.0 Appeals:
3.0.1 Any applicant whose permit application has been denied by the Environmental Health Specialist may
request a review by the local Board of Health.
3.0.2 A request for review must be made within 60 days after denial of an application by the Environmental
Health Specialist.
3.0.3 The applicant must bear the burden of supplying sufficient evidence to document that the denied
system will be constructed and used in such a way as to comply with the declaration and intent of these
guidelines and all applicable state and local rules and regulations and required terms and conditions in any
permit issued pursuant thereto.
3.0.4 Such review must be conducted pursuant to the requirements of C.R.S.,244-105.
3.1 Penalties:
It is a Class 1 petty offense to:
3.1.1 Construct,alter,install,or permit the use of any ISDS without first having applied for and received a
permit
3.1.2 Construct alter,or install an ISDS in a manner that involves a knowing and material variation from the
terms or specifications contained in the application or permit
3.1.3 Violate the terms of a cease and desist order that has become final.
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52
Appendix 4
PROPORTIONS OF SAND, SILT, AND CLAY
IN THE BASIC SOIL-TEXTURAL CLASSES
10o
90
.o
so
�o
MAY
y s L%
YLTY Q�
0.AY
40 6ANOY
MAY
MAY su Mwv ^�
30 LOAM LOMA
SANGGLAY
wAM
20
L AM �Y
/\41
10
6ASANDYLOAM SILT LOAM 4
LOB SILT
SAN SAN
PERCENT SAND
U.S.Standard Sieve Numbers
10 20 4050 200
SAND
SILT CLAY
a d S o• S S 8
0 i 0 0 0 0 0
Grain Size
Source: EPA Design Manual for Land Treatment of Municipal Waste-
water.
53
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54
definition,7
-A- disposal of waste materials,29
distribution box,32,33,37
absorption bed,29,36,42 definition,7
definition,7 Division,5,15,30,31,35,43,46,49
absorption system,8,17,31,33,35,39-41,46,47 definition,7
definition,7 dosing,33,35,37,40
absorption trench,8,24,25,36,37 dosing tank,13,24,33,41
definition,7 definition,7
absorption trenches.See seepage beds drywell,24,32,36
access ports,31 definition,7
aerobic sewage treatment system,28
definition,7 -E_
alternating systems,33
applicability of regulation,5 easements,25
average daily flow,5,21,42 engineered systems, 19,39
Environmental Health Specialist,l3-15,17,29,30,35,40,
-B_ 43,46,51
definition,7
bedrock,14,17,40,41 Er systems.See evapotranspiration systems
definition,7 evapotranspiration system,24,41,42
bedroom,9,21,27,35,39,45 definition,7
definition,7 experimental system 15,19,46
blasting,33 definition,8
_C_
cabins,9
cease and desist orders, 14,51 filter,31
certificate of occupancy,9, 11 definition,8
cesspools,32 final approval,9, 11, 15, 19,49
chamber,7,8,19,29,31-33,35,37,40 floodplain, 12,32
definition,7 floodway.See floodplain
chambered systems.See gmvelless systems formula for system size,35
chemical toilets,45
component design criteria,31
composting toilet
definition,7 gravelless systems,35
composting toilets,9,45,46 gravelless/chambered systems,35
definition, 7 gray water systems,9,27,45
constructed wetland,43 grinder pump.See non-clog pump
definition,7 groundwater, 17,31,40,41
constructed wetland systems,43
conventional systems,35
identification of components,31
incineration toilets,45
deep gravel,35 indicators of failure,31
deflection of runoff,32 individual sewage disposal system,ISDS`or"system"
Department,5,9,11-15,23,25,29,31,35,36,39,41-43, definition,5,7,8, 12
45-47,49 inspection and maintenance,29,31
definition,7 inspection stages, 15
design flow,21,25,27,35,39,42,45 installation,5, 13, 15,25,31,33,36,41,43,45
design requirements,21,27,35,39,40,45
dispersal system,24,47
55
-M- seepage bed,24,25,36,37
definition. See absorption bed
maintenance and cleaning,29 seepage beds,25,36
malfunctioning system, 14 seepage pit,24,36,30,32
maximum flow,21 definition,8
mechanical components,33,46 septic tank,9,13,24,28-33,37,42,45
method of aeration,28 definition,8
monitoring and sampling,29 septic tank design criteria,27
mound systems,40 serial distribution,37
multi-family dwellings,45 definition,8
service label,29
-N- serviceability,31
sewage pumping system,32
non watertight components,32 sewage treatment works,15
non-clog pump,32 definition,8
notice of violation(NOV), 14 situations requiring engineered design, 19
soil profile, 11, 17
-p- soil test,8, 11, 17
structural integrity,31,36
perc test, 11, 12, 17,35,36, summary of ISDS permit process, 11
percolation tests("perc tests") system size calculations,35
definition,8
permit application, 12
permit expiration, 13 -T
permit process, 1 I tank anchoring,31
permit required,9
pipe standards,31
-U-
privy,9
definition,8 unsuitable areas, 15
prohibition of ISDSs, 15
public sewer,5,9 _
pumping of septic tanks,29,45 -V
vault,7,45
-R- definition,8
vault privy,45
recycling systems,46
reductions,33,35
repair permit 13, 14 _
Rural and Remote, I l -`7fj7
water supply,11,12,23-25
-S- definition,8
water table, 14, 17,41,48
sampling well,40 well, 11, 12,23,24
sand filter, 19,24,40,41,47,48 wetlands, 19,43
definition,8 definition,7
56