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Environmental Health - Health Code Regulation 1

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The Missoula City-County Health Code is a document to be considered in its entirety. All regulations are subject to the administrative portion of the document.

Regulation 1: Wastewater Treatment and Disposal Systems (PDF Version) | MS Word

REGULATION 1: WASTEWATER TREATMENT AND DISPOSAL SYSTEMS (February 2007 Version) - Continued...

• GENERAL
• DEFINITIONS
• PERMITS
• SITE EVALUATIONS
• DESIGN AND INSTALLATION OF CONVENTIONAL SYSTEM
• INSPECTIONS
• PRIMARY TREATMENT REQUIREMENTS
• CONVENTIONAL SECONDARY TREATMENT
• ALTERNATIVE TREATMENT SYSTEMS
• WATERLESS SYSTEMS, WATERTIGHT VAULTS, AND CHEMICAL TOILETS
• EXPERIMENTAL SYSTEMS
• REPLACEMENT SYSTEMS
• INCREASED USE AND CHANGES OF USE
• ABSORPTION BEDS
• SEEPAGE PITS
• MULTI-USER OR PUBLIC SYSTEMS
• SPECIAL MANAGEMENT AREAS
• CERTIFIED INSTALLERS AND SITE EVALUATORS

APPENDISES

• APPENDIX A - SOIL PYRAMID
• APPENDIX B - CONSTRUCTION DETAILS FOR SEPTIC SYSTEMS
  
  • DRAWING OF SEPARATION DISTANCES
  • DRAINFIELD DESIGN LAYOUT
  • ABSORPTION TRENCH DETAILS
• APPENDIX C - DOSING DISTRIBUTION BOXES
• APPENDIX D - MISSOULA WASTEWATER TREATMENT PLANT SERVICE AREA
• APPENDIX E - RATTLESNAKE VALLEY SPECIAL MANAGEMENT AREA
• APPENDIX F - LINDA VISTA SPECIAL MANAGEMENT AREA
• APPENDIX G - LINDA VISTA CRITICAL AQUIFER PROTECTION AREA
• APPENDIX H - SUBDIVISIONS WITH STEP TANKS REQUIRED

REGULATION 1: WASTEWATER TREATMENT AND DISPOSAL SYSTEMS

• GENERAL
• DEFINITIONS
• PERMITS
• SITE EVALUATIONS
• DESIGN AND INSTALLATION OF CONVENTIONAL SYSTEM
• INSPECTIONS
• PRIMARY TREATMENT REQUIREMENTS
• CONVENTIONAL SECONDARY TREATMENT
• ALTERNATIVE TREATMENT SYSTEMS
  

  Alternative forms of treatment may be approved by the Department and listed as an approved alternative system. Alternative treatment systems shall meet minimum requirements prescribed ARM 17.36.913 and in DEQ-4.

  • (A) Alternative wastewater systems may be approved by the Department to be used in lieu of conventional systems. The applicant shall provide substantial scientific field testing information available concerning a particular system design before the system may be approved as an alternative. The information must indicate that the system will perform over a period of years with proper maintenance for the purpose for which it is designed.
  • Unless a provision under an alternative system provides otherwise, all rules pertaining to conventional drainfields and septic tanks shall apply to alternative systems.
  • Alternative systems may require additional inspections during and after installation and an additional inspection fee may be charged for each inspection. The Department shall provide a written report of each inspection to the system owner listing deficiencies of the system and correc­tions needed for the system.
  • Use of an alternative system may preclude future divisions of the property pursuant to State requirements. The applicant and future owners shall assume responsibility for any restrictions, liabilities or encumbrances that are caused by the use of an alternative system.
  • All alternative system designs shall provide for replacement areas equivalent to those required for conventional systems in the event of system failure.
  • The Department may place any restrictions or requirements on the design, installation and operation of an alternative system that it deems necessary to ensure that the system will achieve the desired results in any installation. Such restrictions or requirements include but are not limited to temporary or ongoing monitoring, discharge limitations on pollutants, and provisions to ensure proper maintenance and operation of alternative systems. In such cases the Department shall be permitted access to the property to ensure such restrictions or requirements are carried out. Failure to properly follow permit restrictions or conditions, or failure to properly maintain an alternative system is a violation of this rule and grounds for permit revocation.
  • Design criteria for the alternative systems approved for use by the Department are available at the Environmental Health Division Office.  (Back to Top)
• WATERLESS SYSTEMS, WATERTIGHT VAULTS, AND CHEMICAL TOILETS
  • Pit Privies
    1. Pit privies shall not be permitted when the structures served have plumbing fixtures or running water. Pit privies shall be prohibited on small lots in areas characterized as residential or commercial developments.
    2. Pit privies shall not be installed closer than 100 feet from a stream, lake, well or other water supply.
    3. Unsealed pit privies may be approved only for seasonal use in remote locations that are not accessible to septic tank pumpers.
  • Sealed Pit Privies
    1. Sealed pit Privies may be used only at seasonal public recreational facilities operated by governmental institutions or a licensed campground.
       
       • (a) For the purpose of this rule “seasonal use” means use for not more than a total of four months (120 days) during any calendar year. Permit applications for holding tanks must show that the property use conforms to the “seasonal use” limitation or that a variance has been granted. The use of sealed pit privies must cease when the property on which they are located is no longer a public recreational facility operated by a governmental institution or a licensed campground.
    2. Sealed pit privy systems may be approved only if the structure to be served does not have a piped water supply. Permit applications for sealed pit privies must include plans for the proposed sealed pit. Sealed pit privy systems must meet the design and construction requirements in Department Circular DEQ-4.
    3. A sealed pit privy may be required instead of permitting a pit privy if the Department determines that waste from the pit privy could potentially pollute groundwater or cause a nuisance.
    4. A sealed pit privy may be used in a floodplain or flood-prone area or high ground water area provided that the floor surface is one foot above flood plain elevation and the mass of the structure is adequate to prevent the vault from floating during a flood when the vault is empty. Except for floodplain or flood-prone area separation, permanently sealed pit privies shall follow the location requirements for septic tanks in section V(C). This provision does not release the applicant from obtaining required flood-plain permits.
    5. Sealed pit privies must be emptied as needed by a licensed septic tank pumping service.
  • Composting or Waterless Toilets and Other Conservation Methods. Waterless toilets are permitted. A properly sized septic tank/absorption system is also required if a piped water source is provided to the structure served by the waterless toilet.
  • Chemical Toilets. Chemical toilets may be used for temporary events, construction sites and at other locations where a permanent system is not required. Chemical toilets shall not be used to serve as a sewer system for structures.  (Back to Top)
• EXPERIMENTAL SYSTEMS
  • Treatment systems not specifically allowed under this regulation may receive a permit for an experimental system. Experimental systems shall only be considered under the following conditions:
    1. The applicant shall provide adequate information to the Department that ensures the system will effectively treat the wastewater in a manner that will prevent groundwater contamination and will meet all of the requirements in section I (A) and ARM 17.30.9 at all times. Failure to meet the requirements of section 1(A) and ARM 17.30.9 or any permit conditions shall invalidate the permit and be grounds to order cessation of use of the system and buildings that the system serves.
    2. The application shall include a complete description of a scientific evaluation process to be carried out by a scientific, educational, governmental or engineering organization.
    3. The applicant shall provide for any funding necessary to provide adequate design, installation, monitoring, and maintenance.
    4. The system shall be designed by a Professional Engineer, sanitarian or other professional acceptable to the Department.
  • A maximum of three experimental permits may be issued per year countywide.
  • The Department may place any requirements or restriction it deems necessary on a permit for an experimental system. All provisions of Health Department regulations shall apply to experimental systems except those specifically exempted by the permit. A permit to construct an experimental system is not transferable from person to person. Applicants shall provide for inspections to be made by persons approved by the Department. Monitoring and inspection results shall be submitted annually to the Department for up to five (5) years. The Department may refuse to issue a permit for an experimental system for any reason related to the proposed system. The Department may require a redundant conventional system.
  • Any person who sells a property containing an experimental system shall disclose all permit, monitoring and maintenance requirements to the buyer.
  • Experimental systems may be re-classified by the Department to the designation of alternative system after sufficient evidence has been collected to show that the system functions satisfactorily over time.
    
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• REPLACEMENT SYSTEMS
  • No person shall operate a wastewater treatment and disposal system that has failed, as defined in section II of this regulation. Failed systems shall be replaced and meet the following requirements.
  • Replacement systems shall be designed and constructed to allow the best treatment practicable. Drainfields will be required for all situations where there is adequate room and shall be required for replacement when there is potential for contamination of groundwater or surface water.
  • If room is unavailable for a drainfield, then an absorption bed shall be required as a second alternative before a seepage pit is permit­ted. An absorption bed shall be required unless a seepage pit may be permitted pursuant to Section XIII (D) or (E) below.
  • Seepage Pits shall only be allowed for replacement systems in cases where inadequate room or other conditions prohibit a drain­field or absorption bed. Seepage pits may only be constructed or allowed to remain in use in situations where groundwater is shown to be a minimum of 25 feet below the bottom of the proposed seepage pit.
  • Seepage pits may be permitted for replacement systems in areas that are expected to receive public sewer service within five years, as determined by the Department. Seepage pit replacement permits will be temporary, and the owner must execute a deed restriction waiving the right to protest an SID or RSID for the installation of public sewer and agreeing to connect to public sewer within 180 days of its availability to serve the property, as required in Section XV (A) (1).
  • Four (4) feet of separation between the bottom (floor) of any replacement absorption system and the high groundwater elevation or bedrock shall be required. Seepage pits shall require a 25-foot separation to groundwater from the bottom of the pit. Pump systems are required when these minimum separations cannot be met.
  • Seepage pits and cesspools shall be filled with soil, sand, concrete or other approved material when they are replaced with an absorption bed or drainfield.
  • Replacement of systems in floodplain.
    1. A system in a floodplain or flood-prone area that was legally installed with a valid permit may be replaced with an elevated sand mound or other drainfield-equivalent secondary treatment. The bottom of the drainfield must be above floodplain elevation or the system must include advanced secondary treatment before wastewater is discharged into the soil.
    2. Replacement tanks and pump chambers must be designed to prevent floating in a flood.
    3. A system that was not legally installed must be replaced with a system that is in full compliance with this Code.
  • Drainfields in Fill. Drainfields may be installed in fill only for replacement of failing systems.
    1. Location
       • Any parcel that will undergo land modification by filling must have enough area suitable for absorption system placement. The entire area necessary for the replacement absorption system must be filled with appropriate soils prior to final approval of the system.
       • Fill systems may not be installed on soils with a percolation rate slower than 60 minutes per inch. Three percolation tests are required in the native material before fill is installed. Side slopes on the fill may not exceed 25 percent (4:1).
    2. Fill material
       • Soils used for fill may not be finer than sandy loam with a maximum of 20 percent passing the No. 100 sieve.
    3. Design
       • System configuration, dimensions, and orientation must be approved by the Department prior to the placement of fill material.
       • Fill must be of suitable depth to provide the minimum separation distances from the finished ground surface to a limiting layer. Fill shall not be used to overcome minimum vertical or horizontal separation distances in Sections V (B) and (C) of this regulation.
       • Three percolation tests evenly spaced across the completed fill must be performed at the depth of the proposed infiltrative surface as a basis for design application rate.
       • The absorption system must be sized on the basis of the percolation rate for either the soil beneath the fill material or the percolation rate of the fill material, whichever is slower.
    4. Construction
       • All vegetative cover must be removed for the area to be filled.
       • Fill material must not be put in place when the fill or the original soil surface is frozen.
       • Fill material must be placed in lifts specified by the engineer to obtain stable soil structure conditions.
       • Absorption trenches must be set back at least 24 feet from the lower edge of the filled area on slopes of 6 percent or greater. For slopes less than 6 percent, absorption trenches must be set back at least 3 feet on all sides prior to starting the side slope.
       • The fill area must be seeded with a suitable grass to aid in stabilization.
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• INCREASED USE AND CHANGES OF USE
  • No person may increase use to an existing system or operate an existing system that has increased use unless the system meets all current requirements of this regulation or a temporary increased use permit is granted pursuant to Section III (D).
  • To increase use to an existing system in MWTPSA, a person shall file a waiver of protest as described in Section XVII(A)(1) of this rule.
  • No person may install, cause to install or operate additional wastewater systems on a parcel of land or subdivide a parcel of land with a cesspool or other system that does not meet the requirements of Section I(A) of this regulation. Substandard systems must be upgraded to meet Section I(A), provide primary and secondary treatment and reserve a full replacement area that meets current requirements of this regulation.
  • No person may connect to a wastewater treatment and disposal system when the system or connection point (in the case of a multiple connection system) has been unused or disconnected from any residence or structure for more than one (1) year unless the system meets the requirements of Section I(A) of this regulation; has primary and secondary treatment; and meets the separation requirements in V(B) & (C) of this regulation.
  • No person may operate a system that serves a structure if the structure undergoes substantial improvement unless the system meets the requirements of Section I(A) and provides primary and drainfield-equivalent secondary treatment.
  • No person may replace a mobile home with a permanent structure unless the absorption system is located at least 100 feet out of the floodplain and flood-prone areas and all the conditions in XIII(H) regarding expansions of structures are met.
  • The following conditions apply to expansions of structures:
    1. No person may begin construction on a structure expansion until Department issues either a septic permit or a written determination that no septic permit is needed for the proposed project, and;
    2. No person may build over any portion of a system except the pipe from the structure to the septic tank. The exit pipe must be schedule 40 PVC and adequately protected from settlement. Foundation walls must be at least 10 feet from the tank(s) and absorption system, and;
    3. An adequate replacement area must be preserved that is at least equivalent to what was available before the proposed expansion, and;
    4. The system must provide primary and drainfield-equivalent secondary treatment, and;
    5. The system must meet section I. , (A), (1) of this regulation, and;
    6. If public sewer is available as described in section I, (A), (C). The applicant shall connect to public sewer.
  • Septic Determinations for Enlargement of Structures.
    1. A completed application for a determination must be submitted on forms provided by the Department and must include the following:
       • Applicant name and mailing address
       • Property owner and mailing address
       • Address and legal description of property
       • A Brief description of proposed project
       • A site plan, on paper no larger than 11" x 17", accurately showing all buildings, wells, septic systems, replacement area, surface water an floodplains on or within 100 feet of the property.
       • Detailed floor plans, on paper no larger than 11" x 17", showing the proposed project.
       • Other relevant information as required by the Department to clearly define the scope of the project and to ascertain compliance with this Code.
       • Evidence that zoning and building officials have been notified
       • Septic determination application fee
    2. Unapproved changes in plans or specifications after a determination is issued or any falsification or significant error in information submitted by an applicant invalidates the determination.
    3. The Department may place conditions in a determination regarding future use of the enlarged structure to facilitate compliance with the provisions of this regulation.
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• ABSORPTION BEDS
  • Absorption beds may be used as replacement wastewater systems on existing lots where standard absorption trenches cannot be used. Absorption beds may be used as replacement systems for seepage pits. Absorption beds may not be used on new lots unless the system existed before the proposed subdivision, has been in continuous use, and was permitted by the Department. Absorption beds may be used as replacement for previously approved seepage pits when a re-write of the certificate of subdivision approval is completed.
  • An absorption bed is similar in operation to a drainfield but is constructed as shown in Appendix C. Since the operation of the absorption bed depends on the infiltration capacity of the bed bottom, care must be taken during construction so that the bottom of the bed is not compacted by equipment.
  • No person shall install an absorption bed in soils finer than a silt loam or having a percolation rate slower than 60 minutes per inch.
  • All the requirements for conventional drainfields shall apply to absorption beds except for specific requirements listed below.
    1. Design.
       • Absorption beds shall have a minimum of two distribution lines.
       • Absorption beds shall be designed using the application rates shown in Table IV:
       • The distribution lines within an absorption bed shall be uniformly spaced no more than four (4) feet or less than four thirty (30) inches apart. The distribution lines shall be installed no more than two and one-half (2-1/2) feet or less than one and one‑half (1-1/2) feet from the side wall of the bed.
       • The depth of absorption beds shall be no less than 12 inches and no more than 36 inches deep.
       • Both the floor of the absorption bed and the distribution lines (at least 4 inches of perforated PVC for gravity distribution) shall be level.
       • Pressure dosing or pressure distribution must be used
       • When the bed has been excavated, the sides and bottom of the bed shall be raked to scarify any smeared soil surfaces and loose material shall be removed.
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• SEEPAGE PITS
  • Seepage pits must be installed to meet the following requirements and be designed in accordance with DEQ 4 chapter 27.
    1. A seepage pit shall have a concrete ring with a minimum diameter of three feet and a minimum height of 3.5 feet.
    2. Seepage pits shall be sized according to the permeability of the soils where wastewater will be discharged.
    3. A seepage pit that is excavated to four-foot depth and a five-foot diameter shall be equivalent to 50 square feet of absorption area.
    4. Where more than one set of rings is required, the minimum edge-to-edge separation between the edges of the rings is three feet.
    5. The area immediately surrounding the chamber shall be filled with a minimum average of three (3) feet of clean rock or gravel at least three (3) inches in diameter.
    6. The conventional location requirements in section V(C) shall be used, if possible, for seepage pits. Justification: addressed in Section XIII above.
• MULTI-USER OR PUBLIC SYSTEMS
  • Minimum Lot Size - Public or Multiple User Water or Wastewater System Required.
    1. If a proposed subdivision submitted to the Department pursuant to the Montana Sanitation in Subdivisions Act (MCA Title 74, Chapter 4) contains 15 or more parcels less than one acre in size, or if the subdivision will contain more 25 or more people for at least 60 days during a calendar year, a public water supply system or a public sewage system as defined in MCA 75-6-102 must be provided for the lots less than one acre in size.
    2. If a proposed subdivision contains 3 through 9 parcels less than one acre in size, the subdivision must provide one of the following for the lots less than one acre in size:
       • a public water system as defined in MCA 75-6-102 or a multiple family water supply system as defined in ARM 17.36.101and designed by a professional engineer, or
       • a public sewage system defined in MCA 75-6-102 or a multiple family sewage system as defined in ARM 17.36.101. 0
  • Plans for public and multi-user wastewater treatment and disposal systems shall be approved and permitted by the Department. The applicant or installer shall notify the Department not less than eight (8) working hours prior to completion of the system that an inspection will be necessary. Public systems shall also be approved by the State Department of Environmental Quality. Plans shall be designed to comply with this regulation and with requirements of the State Department of Environmental Quality in effect at the time the plans are submitted.
  • Community wastewater disposal systems shall be designed by a registered professional engineer. Written certification shall be required from a registered engineer that the system was installed according to plans. A copy of the "as built" shall be filed with the Department within thirty days of inspection.
  • Multi-user, community, and non-community systems shall be designed in accordance with DEQ Circular 4 and according to this rule. Multi-user and community systems built in the MWTPSA shall also be designed and built to City standards. Multi-user systems shall be designed by a registered professional engineer when more than 1000 square feet of absorption area are required. A maintenance and operation plan, designating who is respon­sible for maintenance and operation of the system, shall be submitted to the Department. Maintenance and operation shall be carried out according to the approved plans.
  • Multi-user, community, and non-community systems shall have all primary and secondary treatment installed for all parcels served before the system is put into use. In the case of a phased subdivision, the treatment system installed shall be adequate to serve a particular phase before the system is put into use. Multi-user and community systems must be installed within two years of permit issuance and before structures are occupied.
  • Any connection to a multi-user system which requires individual septic tanks shall be permitted and inspected by the Department. Individual connections to a community system shall be inspected by the certified operator for the system or by the design engineer.
  • Screens, rock filters or other devices approved by the Department shall be required where individual septic tanks shall connected to a Multi­family or community drainfield.
  • Absorption systems proposed to serve separate buildings located on three or more lots must satisfy the following requirements before a permit will be issued. These requirements ensure the system is installed according to plans, completed in time to serve any occupied structure, and properly operated and maintained with a designated person, partnership, corporation, district, association, or other entity identified as having a clear legal duty to operate and maintain the system.
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    1. The applicant for a permit shall provide a performance bond or other satisfactory security in the amount of the estimated cost of the proposed system, in favor of Missoula County, to secure performance of the installation of the system according to approved plans before occupancy of any structure to be served by the system and in any case within 24 months after issuance of the permit.
    2. The performance bond or other satisfactory security shall remain in effect until the system is installed according to approved plans. A multi-user or public system must be installed, inspected, and approved within 24 months after issuance of the permit.
    3. "Other satisfactory security" may include, but is not limited to, one or more of the following: Special Improvement District, Rural Special Improvement District, county or municipal sewer district, performance or property bond, escrow agreement, lien on property, or similar security arrangement approved by the Department and made a condition of the permit.
    4. The performance bond or other satisfactory security shall be released following installation of the system in accordance with approved plans, after inspection by the Department.
    5. If the Department determines that installation of the system has not been in substantial compliance with approved plans, the Department shall furnish the applicant with a written notice of specific deficiencies to be remedied within a reasonable time not to exceed two (2) months. Missoula County shall be entitled to retain sufficient security to ensure substantial compliance. Missoula County shall be entitled to proceed against the perfor­mance bond or other security and utilize the proceeds to construct the system in accordance with approved plans if the applicant fails to remedy all defi­ciencies within a reasonable time stated in the notice.
    6. The applicant for a permit shall provide the Department with information as to the ownership of the system and all components thereof. The applicant shall provide to the Department satisfactory evidence that a designated person, partnership, corporation, district, association or other entity has a clear legal duty and the ability to operate the system. "Satisfactory evidence" may include, but is not limited to, a special improvement maintenance district, county or municipal sewer district, homeowners' association agreement, or a contractual obligation to operate and maintain the system together with the apparent means and ability to perform. A person desig­nated as the operator of a public wastewater disposal system shall be certified in accor­dance with Title 37 Chapter 42, Part 3 M.C.A. The ownership of the system and responsibility for operating and maintaining it shall be designa­ted on the permit as a condition thereof.
  • A Multi-user and community system must be installed on a separate utility lot, in a common area, in an easement or on the same lot as all the structures served, so that it can easily and legally be accessed by the system's users for maintenance and repair of the system.
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• SPECIAL MANAGEMENT AREAS
  • Missoula Wastewater Treatment Plant Service Area (MWTPSA). The purpose of the MWTPSA requirements are to place landowners on notice that permission to use wastewater disposal in this area is temporary and is intended to be replaced with discharge to a public sewage treatment plant. The following restrictions shall apply to all land within the Missoula Wastewater Treatment Plant Service Area depicted on the map in Appendix D:
    1. The Department shall not issue a permit for an increased use or new wastewater absorption system permit, or a replacement seepage pit system permit issued in accordance with Section XII (E)), in the MWTPSA unless the owner(s) execute a deed restriction waiving the right to protest the creation of a Special Improvement District (SID) or a Rural Special Improvement District (RSID) for the installation of public sewer, using the language set forth below. The filing of a deed restriction shall not be required if previously filed for the same parcel, or where similar language has been shown on an approved and filed subdivision plat.
       
       "I/We, the undersigned, hereby certify that I/we are the owners of the real property located at (legal description) which is located in an area where public sewer is planned to be installed. I/we hereby waive any right to protest an RSIDs or SIDs affecting said property for the purpose of financing the design and construction of a public sewer benefiting said property. Further, my/our signatures on this waver may be used in lieu of my/our signature(s) on an RSID or SID petition for the creation of one or more RSID or SID petitions for the purpose of financing the design and construction of a public sewer benefiting the above-described property. This deed restriction is granted to the County or City of Missoula in exchange for permission to discharge sewage into the ground until such time that public sewer is installed.
       
       This deed restriction shall also constitute an agreement whereby the owner(s) shall connect to public sewer within 180 days after public sewer mains are installed and available to the property.
       
       This waiver shall run with the land and shall be binding on the transferees, successors, and assigns of the owners of the land described herein.
       
       All documents of conveyance shall refer to and incorporate this waiver."
    2. All new divisions of land, including all subdivisions as defined in Section II within the MWTPSA shall exhibit language consistent with section XV, (A), (1). of this regulation on the face of the recorded plat or on a deed restriction recorded with the plat. Language approved by the City and County Attorney shall be available at the Department.
    3. Any person installing a new or replacement septic tank in an area of the MWTPSA designated for STEP (on Appendix D) or approved for STEP via any applicable subdivision approval process shall install a STEP septic tank with manway. A list of subdivisions containing lots which require STEP tanks as a condition of an applicable approval process is contained in Appendix G.
    4. Individual and multi-user or community septic tanks, and multi-user or community system mains and service lines installed in the MWTPSA shall conform to the design criteria established by the City of Missoula Engineering Department. The design, installation and inspection of all mains, service lines connected to mains STEP tanks and related appurtenances must be approved by the City of Missoula Engineering Department. As-built plans for all multi-user, community, or dry laid systems must be submitted to the City of Missoula Engineering Department and the Department by the applicant within 60 days of installation.
    5. If a property in the MWTPSA is part of a proposed division or subdivision of land, as defined in MCA 76-3-102 containing three or more lots of less than five acres per lot, the developer must provide a multi-user or community system that may be easily connected to public sewer when sewer mains are available to service the property except as provided below.
       • In areas where STEP tanks are required and the division or subdivision of land contains no more than fourteen lots in all phases approved after September 21st, 1994, a properly designed, installed and inspected dry laid pressure main connecting the lots with appropriate easements may be used.
       • In areas where STEP tanks are not required and the division or subdivision of land contains no more than fourteen lots in all phases approved after September 21st, 1994, a properly designed, installed and inspected dry laid pressure or gravity main connecting the lots with appropriate easements may be used with written permission and approval from the City Engineering Department
       • When the division of land includes perpetually dedicated common areas and wildlands or an area reserved from development by deed restriction until public sewer becomes available, the Department shall divide the area of such dedicated land by the number of lots and add the result to each lot area for the purposes of determining applicability of this requirement.
       • All portions of the proposed multi-user or community system, except for on lot service lines, shall be installed before the system may be used. Installation of the system may be phased with the Department's approval so long as the system is installed within two years of final plat approval and an improvement guarantee approved by the Department is provided by the developer.
  • Rattlesnake Valley Special Management Area. The following restriction shall apply for wastewater treatment and disposal systems in that portion of the Rattlesnake Creek Drainage above the Mountain Water intake dam which is classified as A-closed by DEQ (see Appendix E). A wastewater treatment and disposal system serving one single family dwelling or other use with flows less than or equal to a single family dwelling per lot or parcel will be allowed provided that all other requirements are met. The Department may not issue any permits or approve any Certificates of Subdivision Approval for subsurface disposal of wastewater for any new divisions or subdivision of land inside the special management area. The Department may place any conditions on a wastewater treatment and disposal system permit it deems necessary to ensure compliance with the A-closed classification standards, including but not limited to requiring an alternative treatment system such as a sand filter, trickling filter or other system effective at removing pathogens.
  • Linda Vista Special Management Area. (see Appendix F) The Department shall approve no permits for subsurface disposal of wastewater inside the special management area. The Department shall approve no lifting of sanitary restrictions for any new divisions or subdivisions of land inside the special management area, unless they are served by municipal sewer.
    
    The following restrictions apply to all buildings within the Linda Vista public sewer master plan area that produce sewage effluent (see Appendix F). The owners of regulated buildings inside the entire Linda Vista public sewer master plan area (see Appendix G) shall cease discharge of sewage to the subsurface and shall connect to public sewer within 90 construction-season days after a transfer of ownership if public sewer mains are installed and located within 200 feet of the property.
  • Roman Creek/Touchette Lane Special-Management Area. The following restrictions shall apply to all land included within the E 1/2 of Section 29, W 1/2 of Section 27, Section 28, T15N, R21W, bordered on the north by the Frenchtown Irrigation Canal and bordered on the south by U.S. Interstate 90.
    1. All parcels with existing plat approvals shall be permitted to install systems if the site meets the four (4) foot separation required from the bottom of the disposal trench to high seasonal groundwater. High groundwater testing may be required to satisfy this requirement.
    2. The Department shall perform a preliminary inspection of the site with the excavator at the start of construction to ensure that:
       • maximum depth is maintained; and
       • the absorption system is located properly.
    3. Wells shall be grouted to a minimum twenty (20) feet. Bacterial samples are recommended and disinfection may be necessary to ensure a potable water supply. A copy of the well log shall be submitted to the Department showing adequate compliance with the plat approval and Montana DNRC Well Drilling Requirements.
    4. The Department may not approve further subdivision in the area until the cause of water contamination is discovered and the problem corrected.
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• CERTIFIED INSTALLERS AND SITE EVALUATORS
  • Certification. All installation, construction, extension, alteration or repairs of wastewater treatment and disposal systems that requires a permit in accordance with Section III shall be supervised by a person who has passed an examination as described in subsection (2) below to ensure they have sufficient knowledge and training to complete the work in compliance with this regulation before installing any system in Missoula County. Upon passing the exam, an installer shall be certified for the calendar year in which the exam was taken. Certification shall expire annually on December 31st.
    1. Certification allows installers to install or repair wastewater treatment and disposal systems in Missoula County . A certified installer shall be on site at all times during installation.
    2. To become certified installers shall take a Class II exam, which allows the installation of conventional and replacement systems and may take a Class I exam, which allows the installation of experimental and alternative systems.
    3. Applications for certification and certification renewal shall be in writing on forms provided by the Department and shall include the name, address and phone number of the applicant and the name of the business that the applicant is repre­senting. Applications shall be accompanied by an application fee determined by the Board to defray the costs for training and exams.
    4. Certified commercial installers must pass an annual take-home exam for re-certification. These exams shall be submitted to the Department with the application for re-certification.
    5. Certified installers shall have evidence of certification at the installation site available for inspection by the Department and a copy of the appropriate permit.
    6. The Department shall not approve a system when there is no certified installer on site during an installation until a certified installer completes the system or until the installer becomes certified and the system meets all requirements. When there is no certified installer on site during an inspection the Department shall charge a reinspection fee to return and reinspect the system when a certified installer is on site. The Department may waive the requirement to have a certified installer on site during an inspection by arrangements made prior to the inspection.
    7. Certification may be revoked by the Department from an individual or from a single employer and its employees for any of the following reasons:
       • A single occurrence of installing or attempting to install a system without a valid permit
       • A single occurrence of deliberately falsifying an inspection.
       • Repeated mistakes in installing a system with regards to the require­ments of this regulation. The Department shall issue two written warnings in a two-year period prior to revoking an installer's certification
       • Failure to correct deficiencies noted during the inspection of an installation.
    8. Revocation of certification may extend for up to one year.
    9. Installers who have their certification revoked may request a hearing before the Board in accordance with the provisions of this Code.
  • Site Evaluators. Professional Engineers specializing in civil, environmental, sanitary, or agricultural engineering; persons with B.S. degrees in geology, hydrogeology, or soils science; and Registered Sanitarians with sufficient soils course work or specialized soils training are authorized to perform site evaluations. Other persons may be approved by the Department if they demonstrate sufficient knowledge of soils enabling them to perform satisfactory site evaluations.
    1. When a site evaluation is required, the evaluation may be performed by a person approved by the Department to conduct site evaluations; or the applicant may request that the Department perform a site evaluation.
    2. Site evaluators or persons under their direct supervision shall be required to conduct percolation tests as described in this regulation on all proposed drainfield sites except that site evaluators who pass a soils textural classification test administered by the Department may have the percolation test requirement waived for sites having soils with textures ranging from a medium sand to a silt loam.
    3. If a site evaluation is conducted by an approved site evalua­tor, the Department may require access to the property where the proposed site is located to confirm information submitted by the applicant. The Department may reject a site evaluation if access is denied.
    4. The Department may refuse to accept site evaluations from persons who have a documented history of supplying incorrect site evaluations or incomplete information as required.

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