5 Colo. Code Regs. § 1002-43.23
The provisions of sections 25-10-101 through 113, C.R.S. provide the specific statutory authority for adoption of this regulation. The Commission also adopted, in compliance with section 24-4-103(4), C.R.S., the following statement of basis and purpose.
Basis and Purpose
The March 2013 hearing culminated the efforts of many parties, both before and after the release of the "Recommendations of the Individual Sewage Disposal System Steering Committee" in February 2002, to improve Colorado's On-site Wastewater Treatment System (OWTS) framework. The Water Quality Control Division and numerous interested parties were engaged in a robust stakeholder process since the summer of 2009 to evaluate and recast the previous Individual Sewage Disposal System (ISDS) Guidelines that had not been substantively modified since 1994.
Because of the many changes and the reorganization of the ISDS Guidelines, the Commission repealed the ISDS Guidelines and adopted the On-site Wastewater Treatment System Regulation, Regulation #43. The new regulation built on the previous ISDS regulation to reflect a more current state of On-site Wastewater Treatment System industry practice and to provide more options and flexibility in design and local regulation.
In addition, provisions were included in the new regulation to incorporate changes made in House Bill (HB) 12-1126, the OWTS Act passed by the Colorado General Assembly in the 2012 legislative session. The major changes include revised versions of previous and addition of new definitions, updated terminology (such as changing "Individual Sewage Disposal Systems" to "On-site Wastewater Treatment Systems"), new requirements for design of OWTS, and optional provisions for local public health agencies to adopt in the areas of OWTS design, permitting, and operation.
An "authority" section was included to indicate the statutory authority for the regulation.
Previous section XII. on discharges to State waters from the ISDS Guidelines was incorporated into section 2. (Scope and Purpose). Content from other sections from the ISDS Guidelines were moved as appropriate. These included moving several sections scattered throughout the ISDS Guidelines into section 4. of Regulation #43 (Applicability).
The terms individual sewage disposal system and local health departments were replaced throughout the regulation by the terms On-site Wastewater Treatment System and local public health agency, respectively, to reflect the terms used in statute.
The major definitions revised or added by the Commission include:
The definition of absorption system from the amended OWTS statute is still included in the regulation. However, the term soil treatment area based on current industry terminology has largely superseded its importance.
A definition of cesspool was added based on the definition in the OWTS statute as included in HB 12-1126.
The definition of drywell was revised to limit its use to non-wastewater sources.
A definition of effluent screen was included as there were several references to this component added throughout the regulation.
Definitions of OWTS failure and malfunction were added, as these are critical terms in implementation of an OWTS program by local public health agencies.
A definition of field performance testing was added for testing during normal operation at a field installation of new treatment systems that are being considered for acceptance by the Division.
The definition of design flow was modified to remove the reference to 150 percent of the average daily flow rate, as this concept is no longer in use for OWTS.
The definition of grey water system was removed as the Commission found that the OWTS application of the separation of toilet wastes with the remaining wastewater being treated in a down-sized OWTS is inconsistent with other uses of the term grey water.
The definition of liner was revised to be written in more general terms and the specific reference to the thickness of the material was incorporated into design criteria.
The definition of long-term acceptance rate (LTAR) was revised to be stated in terms of what the LTAR is rather than how it relates to other factors such as design flow and soil treatment area.
The definition of "mound system" was changed to "mound" and revised to clarify distinctions between mounds and other OWTS.
A definition of performance standard was added, as this concept is fundamental to revisions made in this version of the regulation.
The definitions of sanitarian and seepage bed or absorption bed were deleted based on their being redundant with other defined terms (environmental health specialist and soil treatment area bed, respectively).
A definition of septage was added consistent with the new definition added to the statute by HB 12-1126.
New definitions of site evaluation, site evaluator, soil, soil evaluator, soil profile hole and soil profile test pit excavation were added based on the increased emphasis in the new regulation on the need for robust soils and site evaluations in the design of OWTS. In addition, several technically based definitions were added such as consistence, distribution, several sub-definitions under the definition of dosing, infiltrative surface, inspection port, limiting condition, nitrogen reduction, redoximorphic, remediation system, restrictive layer, riser, rock-plant filter, sequential distribution, soil morphology, soil structure, soil texture, and visual and tactile evaluation of soil. Many of these terms were included to provide context and greater detail to better describe the necessary processes for site and soil evaluation and designing an OWTS.
As previously indicated, content was moved from section II of the ISDS Guidelines to section 4. of Regulation #43. The Commission included several subsections to the Applicability section to identify other Commission regulations that may apply to OWTS with a design capacity of 2,000 gallons per day or greater and to be explicit that the requirements for maintenance and standards of performance (e.g., effluent limitations) will be determined by the site application approval and discharge permit processes for such OWTS. Also, the Commission adopted section 4.A.1.b to indicate that all other aspects of permitting, performance, and construction will be in conformance with the regulations adopted by the local board of health.
The Commission modified, in section 4.B. of Regulation #43, the provision from section IV.A.1. of the ISDS Guidelines to clarify that a permit must be issued by the local public health agency before construction is commenced on a new, altered, or repaired system. New detailed requirements for information to be submitted with a permit application were included.
In conformance with HB 12-1126, the Commission included language in section 4.B.4. on fees to indicate that fees for permits shall be based on the actual direct and indirect costs up to the statutory maximum and clarified that fees for other services such as soil evaluations will also be based on actual indirect and direct costs.
In section 4.B.7., the Commission clarified that the owner of a malfunctioning OWTS is required to obtain a repair permit whereas the applicable section of the ISDS Guidelines (IV.A.5) only required that application for a repair permit be made.
In section 4.F., the Commission established requirements for final approval of a permit for an OWTS.
The Commission included section 4.I. ("Product Development Permits") for proprietary treatment systems undergoing testing under actual operating conditions. It includes application requirements for such systems and other requirements such as for reporting of any data collected and authority for the local public health agency to revoke or amend the permit based on several identified factors.
The Commission, consistent with changes made in HB 12-1126, replaced the provisions of section IV.K.1. of the ISDS Guidelines with section 4.K. removing the requirement to hold a public hearing prior to prohibiting a permit for an OWTS and deleted the provision that such prohibitions are limited to areas where there are more than two dwellings per acre or areas that are subdivided for more than two dwellings per acre. Pursuant to the changes in the statute, the Commission adopted a simpler condition that provides that the areas shall be identified based on applicable local land use laws or areas defined by potential problems.
The Commission, in sections 4.L.1. and 4.L.3., modified the provisions of ISDS Guidelines sections IV.M.1. and 2., respectively, to authorize local boards of health to charge fees for initial licensing of OWTS contractors and cleaners and renewal of those licenses based on the actual cost to the local public health agency rather than the specific amounts in the Guidelines.
The Commission established a new optional transfer of title inspection provision that the local board of health may choose to implement at its discretion. If adopted by a board of health, the local regulation would have to be consistent with the requirements of Regulation #43 except that the local board of health would have the authority to identify types of title transfers that are not required to be inspected. The Commission established application requirements, criteria determining that an OWTS is acceptable, a requirement that unacceptable OWTS be repaired, and other provisions, including for penalties should a property in a local public health agency jurisdiction transfer without obtaining a required inspection. The Commission finds it appropriate to adopt an optional title transfer inspection provision based on interest shown in the stakeholder group for a consistent approach to this practice and that there will be costs to be borne by the local public health agency in implementing the program so a mandate is not appropriate.
Provisions for a new optional renewable permit program were established. These permits could be used to set requirements for activities such as required maintenance, a schedule for required inspections of the performance of higher level treatment systems, when a transfer of title inspection is required or other requirements deemed necessary by the local board of health. Similar to the transfer of title inspection program, stakeholders indicated a desire for a consistent approach and the Commission did not find it appropriate to create a mandate where there would be a cost to the local public health agency.
Content in section XVIII. of the ISDS Guidelines regarding variance provisions became section 4.O. of Regulation #43. The Commission modified the requirements for local board of health hearings regarding variances and required a public hearing to be held on all variances.
The Commission moved content in section XV. of the ISDS Guidelines to section 4.O.7. of Regulation #43. Similarly, the Commission moved the un-numbered "General Prohibitions" section that follows section XV. to section 4.P. and the unnumbered "Penalties" section to section 4.R. The Commission, consistent with a change made in HB 12-1126, removed the prohibition against allowing an OWTS that did not meet required separation distance between maximum seasonal ground water table and the bottom of an absorption system to remain in use without compliance with the Guidelines. The Commission, consistent with section 25-10-112(5) added a new requirement to properly dispose of septage.
The Commission incorporated site and soil evaluation requirements into section 5. of Regulation #43. These include significant revisions to the previous soil test provisions in section VII. of the ISDS Guidelines as well as the addition of more specific information to be provided regarding the proposed site such as a legal description of the property, location of features on and off the property for which setbacks may apply, and the characteristics of the site such as topography.
There had been no specific process identified in the ISDS Guidelines for a site and soil evaluation. The Commission determined that there are several elements of each that are consistent with current standard OWTS design industry practice and therefore appropriate to include in Regulation #43. These include a requirement to conduct an initial site evaluation, a reconnaissance evaluation of the site, and detailed soil evaluations, and prepare a report that documents the required information that will be used to support the design of the OWTS.
The process builds from a "desktop" preliminary investigation to identify site location and ownership information, soils information from available sources such as the Natural Resources Conservation Service, and, most importantly, information on physical features (property boundaries, streams, wells, etc.) from which setbacks will have to be determined. This information, facility information, and local OWTS regulations are used to identify a preliminary OWTS size. This is a sensible first step that will allow the system designer to become familiar with the general information to be refined and verified in the following steps.
The next step the Commission identified is a reconnaissance investigation to identify topography, landscape position, natural and cultural features, and vegetation. This is information that will assist in determining a preliminary location for the soil treatment area (STA) and where the soil investigation will be conducted.
The final step is to conduct the soils evaluation. The Commission found it imperative that this process be based on a thorough physical examination of the soil in the proposed STA. The soils provide critical treatment of the wastewater including reduction of pollutant concentrations and filtration to remove microorganisms before the treated wastewater reaches the ground water. The use of soil profile test pit excavations is accepted practice in the OWTS industry and the Commission, as part of its move to "modernize" the OWTS regulations, adopted this approach to ensure that the required level of treatment in the soils is achieved.
The ISDS Guidelines allowed a soil profile hole to be drilled along with the use of percolation tests. The Commission found that the use of soil profile holes does not provide critical information such as the seasonally high ground water level and limiting layers that are not bedrock. In order to provide for a transition to the use of soil profile test pit excavations, which allow an examination of the in-situ soil profile, the Commission allowed soil profile holes in conjunction with percolation tests to be used for a three-year period from the effective date of Regulation #43. After that time, at least one soil profile test pit excavation will be required if percolation tests are to be used to determine the LTAR. Visual and tactile evaluation in soil profile test pit excavations may be used to determine the LTAR without percolation tests.
The Commission included additional information on the conduct of percolation tests and soil evaluations based on current OWTS industry practice to ensure that the information used to size the soil treatment area is as accurate as practicable.
Percolation tests and soils evaluations are required to be conducted under the supervision of a professional engineer licensed under Colorado law or a competent technician as defined in the regulation. The Commission established expertise that the competent technician must possess to conduct percolation tests and soils evaluations and identified means by which the required expertise can be obtained. The Commission expects that individuals that do not possess this expertise will obtain the necessary training or degree. The Commission is aware that there is training available in soils evaluation, such as that available through the Colorado Professionals in On-Site Wastewater, and, to the extent practical, encourages the Division to ensure that training is available in different areas of the state.
The Commission required the preparation of a report documenting the site and soils information collected, to be used for the design of the OWTS and to determine whether other treatment prior to the STA is necessary. The Commission established elements of the report in order to ensure that the required information was provided for the design of the OWTS and that it was properly collected.
The Commission modified the requirements previously in section V. of the ISDS Guidelines in section 6. of Regulation #43. Modifications include establishing that the minimum size of a new single-family home for determination of the OWTS design flow is two bedrooms and providing the local public health agency the authority to increase the number of bedrooms based on unused space that could be converted into one or more bedrooms. The Commission included these provisions based on its intent that OWTS are often used for thirty or more years and that it is appropriate to size the OWTS based on an assumption that additional bedrooms are likely to be added in these types of situations. Also, the Commission deleted the provision that the maximum flow be 150 percent of the design flow and be used as the basis for the OWTS design. The Commission modified calculations of STA size rather than apply a factor to flow rates.
The other requirements regarding flow (gallons per day) and biochemical oxygen demand (pounds per day) for multi-family, commercial, and institutional facilities remains the same as in the ISDS Guidelines.
The Commission also included in section 6, various treatment levels (e.g., TL2 and TL2N) with associated levels of carbonaceous BOD5, total suspended solids, and total nitrogen that are used in conjunction with provisions in section 7, to determine where STA size or the depth of required soil can be reduced.
The Commission maintained the table of minimum horizontal distances between components of an OWTS and pertinent physical features from section VI of the ISDS Guidelines and added an option for reducing the applicable distance where higher level treatment (e.g., TL2N) is provided. This provides options to reduce the distance between the STA and identified physical features where higher level treatment is provided in contrast to the previous approach under which setback distances from identified features were required to be met regardless of level of treatment unless a variance was granted. This provides flexibility and the beginning of what may be a transition to a performance-based regulatory approach.
Where the distance from an STA to proximate physical features is allowed to be reduced due to provision of higher level treatment, the Commission included a requirement for mandatory operation and maintenance of the system in accordance with section 14.D. of Regulation #43.
The Commission, in section 8. of Regulation #43 (Design Criteria - General), modified the requirements from section VIII. of the ISDS Guidelines to add requirements in section 8.C. to ensure that septic tanks and treatment components are accessible for inspection, maintenance and servicing. The Commission finds that these activities must be performed in order for an OWTS to function properly and in order to protect public health and the environment. This will require installation of a riser at or above the ground surface for tanks, effluent screens and treatment components of new systems. Where risers are not provided or components are buried at a great depth, they often cannot be located when maintenance is required.
Minor modifications to the other provisions from section VIII. of the ISDS Guidelines in section 8. of Regulation #43 were made to clarify or add additional detail. The Commission included section VIII.D.7. of the ISDS Guidelines in section 8.K. whereas the remaining requirements of section VIII.D. were included in section 10 of Regulation #43.
The Commission, in section 9. of Regulation #43, modified the provisions of the ISDS Guidelines to require watertight testing of tanks either at the manufacturing site or at the property where the tank is to be installed. This is necessary to provide documentation of the tank's watertight condition prior to installation. For septic tanks, the Commission required that accepted test methods be used to demonstrate watertight conditions. The local public health agency inspector will conduct a field inspection after the tank has been placed in the final excavation but before the tank is buried and may require a watertightness test. This will aid in evaluating that factory tested tanks have not been damaged in transit. The Commission also modified the requirement that had been in the Guidelines regarding tank anchoring. Instead, manufacturer's instructions may be followed where provided or, where such instructions are not provided or a choice is made to use an alternate approach, a professional engineer is required to design the anchoring system.
The Commission bolstered the provisions for septic tank structural integrity to require that the manufacturer provide documentation regarding what load conditions a tank can withstand, including depth of burial and other loads or pressures including from the seasonally high level of ground water.
The Commission added more specific requirements for structural integrity for septic tanks (concrete and fiberglass/plastic) that identify generally accepted industry standards to be met. Also, more specific requirements for pipe and pipe bedding and pumping and dosing systems were added based on current industry standards and practice.
Consistent with current industry practice for septic tank design, the Commission increased the minimum size of a tank for a residential application to 1,000 gallons and reduced the minimum tank size for OWTS serving non-residential buildings to 400 gallons. The requirements in section 9.B.4.d. of Regulation #43 for inlet and outlet tees or baffles were modified to ensure that installation and servicing of effluent screens can be accommodated. Other minor changes to tank dimension requirements were also made.
The Commission added a provision authorizing the use of effluent screens and providing that the local public health agency can require such screens. Additional requirements to ensure proper cleaning of screens and requiring an effluent screen where effluent is pumped from a septic tank were also included. The Commission encourages the use of effluent screens as they can prevent clogging of STA distribution piping and extend field life.
A requirement for a grease interceptor was added for commercial food establishments and other facilities that generate significant quantities of fats or grease. This is necessary to reduce organic load and wastes that are difficult to treat.
In section 10. of Regulation #43, the Commission laid out significantly more detailed requirements for the design of STA. As previously indicated, the design of the STA is to be based on information developed in the site and soil evaluation.
In section 10.B., the Commission expanded the conditions under which a professional engineer is required to design an STA to include presence of an impervious layer and different soil types rather than the requirements in the ISDS Guidelines that had limits based on presence of bedrock and percolation rate, respectively. This is in keeping with the increased focus on the importance of soil evaluation in the design of an STA.
The Commission adopted a design approach upon which the STA sizing is based on the LTAR rather than a calculation using the percolation rate. Soil percolation values, where collected, can be used to establish the LTAR. Of course, as indicated in section 5. (site and soil evaluation), the design of an STA can be based wholly on a soil evaluation through the use of visual and tactile examination of soils in a test pit excavation. This change in approach is supported by significant research in the field.
The Commission established LTARs based on the soil type and provided for an increase in the LTAR where higher-level treatment is provided prior to the soil absorption system. This approach adjusts the level of treatment that is required in the soil based on treatment having been provided prior to distribution into the STA. The Commission established a specific requirement for a sand filter to be provided where the soils contain large amounts of rock. This is appropriate, as rocky soils will likely allow wastewater to pass through the STA without being fully treated. The depth of the required sand filter is greater (three feet) for TL1 (septic tank effluent) treatment systems than for other (types 2N, 3, and 3N) systems (two feet).
The allowance of reduction in seepage bed or trench area where dosing and chambers are used is continued, although the reductions were adjusted. The Commission also added a reduction for manufactured media based on the reduction of fines in natural gravel and reduced compaction from the deposition of gravel. The Commission, based on research indicating that beds do not perform as well as trenches, included an upward adjustment (STA sizing factor greater than 1.0) for beds in table 10-2.
The Commission maintained the previous provisions regarding distribution systems and trenches/beds in Regulation #43 and also added requirements that limit the width of a bed to 12 feet to aid in air/oxygen transfer to improve aerobic treatment in the soil. Width of beds may be greater than 12 feet if treated septic tank effluent is applied. The width of evapotranspiration beds may be greater than 12 feet because air/oxygen transfer to the soil is not a component of evapotranspiration beds.
The Commission added a provision in section 10.E.1.b. limiting the depth of the infiltrative area to four feet, to improve oxygen transfer. The depth will be measured from the downslope side of the trench or bed. The Commission, in section 10.E.2., limited the length of gravity fed distribution lines to 100 feet and pressure dosed lines to 150 feet. A requirement to install an inspection port at the terminal end of each distribution line was added to allow the STA to be visually inspected to determine whether plugging or a structural problem is occurring. Also, criteria were included for the use of chambers, manufactured media, pressure distribution, sequencing systems, and drip lines as these commonly used design approaches/components were not addressed in the ISDS Guidelines.
The Commission modified the requirements for alternating systems to allow reductions to be given where dosing or manufactured media systems are used. The Commission deleted the required frequency of dosing that had been included in the ISDS Guidelines to allow more design flexibility.
The Commission added specific provisions for repairs allowing the use of deep gravel systems, wider beds, and seepage pits. These technologies had been allowed for new/enlarged systems under the ISDS Guidelines. The Commission determined that these technologies do not provide the same level of treatment or public health/water quality protection as the systems allowed under this regulation. Therefore, their use should be limited to repair situations where an allowed system cannot be properly installed due to site constraints or other limiting factors.
The Commission included additional requirements for new seepage pits to offset, as much as practicable, their performance limitations.
The Commission adopted section 11. for design criteria for higher level systems. This section generally replaces or consolidates the criteria previously in section VIII.B.2. and sections IX. and X. of the ISDS Guidelines. The Commission distinguished between higher level treatment systems using public domain technology design information and proprietary systems. The Commission required public domain technology systems to be designed, installed, and maintained in accordance with established criteria such as applicable references and any conditions established by the local public health agency. Proprietary systems must be designed, installed and maintained in accordance with manufacturer's instructions and any additional criteria established through the technology review and acceptance process in section 13. The Commission established these requirements to ensure that these more complex technologies will perform at the intended level since they are replacing simpler systems that may not rely on mechanical systems that are subject to failure and that require much less operational attention and maintenance. These systems will be assigned a treatment level based on those described in section 6.
In section 13., the Commission added significant detail to the previous provisions for sand filters in section VIII.C.5. of the ISDS Guidelines. These include subcategories for several different sand filter types and associated sizing requirements and minimum requirements. Other detail was added to ensure proper design and performance, such as allowable slope for a mound system and the distance between the bottom of the sand filter and the ground water or bedrock.
The Commission prohibited new wastewater ponds for single-family residences based on the difficulty of maintaining adequate water levels in a small pond in semi-arid conditions. Additional items were added such as maintenance requirements and a maximum allowable seepage rate.
The Commission clarified that vaults may be used for full time occupancy properties where a failing OWTS cannot be replaced or for new systems where an OWTS with an STA is not feasible or for properties where an STA is not allowed.
The Commission provided authorization for local public health authorities to prohibit new and the use of existing vault privies and pit privies.
For incinerating and composting toilets, the Commission clarified that these may be subject to the requirements of a local plumbing agency or the Colorado Plumbers Board, whichever has jurisdiction in the specific location. The Commission added requirements for composting toilets including proper disposal of residue and accounting for low temperatures in the design.
The Commission expanded the provisions for acceptance of new product technology in section 13. of Regulation #43. This included a new requirement and associated elements for an application to be submitted in support of a proprietary treatment or remediation product. Also, product acceptance requirements were established for many types of products ranging from meeting National Sanitation Foundation requirements for composting toilets to detailed field performance testing to demonstrate performance for proprietary treatment products. Details for both the application and acceptance processes were added to provide the Division and technology proponents with a clear understanding of the level of information required and the basis for the Division's decision.
Also, the Commission established specific criteria for acceptance of remediation products that are necessary to ensure that owners of failing systems are not led to believe that the system can be remediated by the use of a remediation product when, in fact, repair or replacement is the only option.
The Commission, subject to a proprietary treatment product having met the NSF/ANSI Standard 40 or equivalent testing program and where at least one unit has been installed in Colorado as of the effective date of Regulation #43, allowed the continued use of a proprietary treatment product with a treatment level of TL2.
The provision of a public hearing where approval of a product has been denied has been removed as it is unnecessary. Final decisions of the Division, including the denial of a technology, may be appealed to the Commission pursuant to sections 25-8-202(k) and 25-8-401, C.R.S. The Commission's decision can be appealed by either party to the district court.
The Commission established new operation and maintenance (O&M) requirements including a mandatory O&M program where higher-level treatment is used as the basis for reduction of a vertical or horizontal setback distance or for a reduction in the STA area. This is appropriate given that the protection of public health and water quality under these circumstances depends on the proper functioning of the higher level treatment system and these systems must be operated and maintained to function at the intended level of treatment.
A local board of health must adopt regulations requiring appropriate O&M in order to offer a reduction in the setback distance or in the size of the STA where higher level treatment is proposed. The local board of health is not required to adopt this provision of the regulation. Where the provisions of the regulation are adopted, however, they must include requirements for the local public health agency to develop a program of inspections, maintenance, recordkeeping, and enforcement to ensure that the systems are meeting the designed higher level treatment standards and maintaining appropriate records.
The Commission included required minimum inspection and maintenance frequencies, depending on the type of higher level treatment (e.g., with or without mechanical parts), and a requirement for system owners to maintain an active maintenance contract at all times. The Commission modified the monitoring provisions of section XIV.D. of the ISDS Guidelines to clarify that a local public health agency can require monitoring where there are indications of inadequate performance, where an OWTS is located in a sensitive area, and for experimental systems and systems under product development permits. The monitoring of experimental systems and systems under product development permits is necessary in order to establish a baseline expectation for system owners and local public health agencies. A local board of health could choose to require additional monitoring at its discretion.
The Commission encouraged stakeholders to consider the following issues in the next review of Regulation #43:
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-43.23