1. (1) Protection of public waters from public health hazards. An agent may not authorize installing or using a system that is likely to pollute public waters or create a public health hazard. If, in the judgment of the agent, the minimum standards in this division will not adequately protect public waters or public health on a particular site, the agent must require a system to meet requirements that are protective. This may include but is not limited to increasing setbacks, increasing drainfield sizing, or using an alternative system. The agent must provide the applicant with a written statement of the specific reasons why more stringent requirements are necessary.
2. (2) Approved treatment and dispersal required. All wastewater must be treated and dispersed in a manner approved under these rules.
3. (3) Prohibited discharges of wastewater. A person may not discharge untreated or partially treated wastewater or septic tank effluent directly or indirectly onto the ground surface or into public waters. Such discharge constitutes a public health hazard and is prohibited.
4. (4) Prohibited discharges to systems. A person may not discharge into any system cooling water, air conditioning water, water softener brine, groundwater, oil, hazardous materials, roof drainage, or other aqueous or nonaqueous substances that are detrimental to the system’s performance or to groundwater.
5. (5) Increased flows prohibited. Except where specifically allowed by this division, a person may not connect a dwelling or commercial facility to a system if the total projected daily sewage flow would be greater than that allowed under the original system construction-installation permit.
6. (6) System capacity. Each system must have adequate capacity to properly treat and disperse the maximum projected daily sewage flow. The projected daily sewage flow must be determined from OAR 340-071-0220 Table 2 or other information the agent determines to be valid.
7. (7) Material standards. All materials used in onsite systems must comply with standards in this division and OAR chapter 340, division 073.
8. (8) Encumbrances. Before a permit to install a new system may be issued, the site for the new system must be approved under OAR 340-071-0150 and be free of encumbrances, such as easements or deed restrictions, that could prevent the installation or operation of the system from conforming with the rules of this division.
9. (9) Plumbing fixtures connected. All plumbing fixtures in dwellings, commercial facilities, and other structures from which sewage is or may be discharged must be connected to and discharge into an approved area-wide sewerage system or an approved onsite system that is not failing.
10. (10) Future connection to sewerage system. DEQ encourages placing plumbing in buildings to facilitate connection to a sewerage system in areas where a district has been formed to provide sewerage facilities.

11. (11) Property lines crossed: All or part of an onsite system, including areas for future repair or replacement, may be located on one or more lots or parcels different from the lot or parcel on which the facility the system serves is located. The lots and parcels may be under the same or different ownership:

    1. (a) For each lot or parcel different from and under different ownership than the lot or parcel served, the owner of the lot or parcel served must ensure that a utility easement and covenant against conflicting uses is executed and recorded in such owner's favor, on a form the agent approves, in the county land title records. The easements and covenants must accommodate the parts of the system, including a 10-foot setback surrounding the areas for future repair or replacement, that lie beyond the property line of the facility served and must allow entry by the grantee, successor, or assigns to install, maintain, and repair the system;

    2. (b) For each lot or parcel different from, but under the same ownership as, the lot or parcel served, the owner of the property must execute and record in the county land title records, on a DEQ-approved form, an easement and a covenant in favor of the State of Oregon:

       1. (A) Allowing the state's officers, agents, employees, and representatives to enter and inspect, including by excavation, that portion of the system, including setbacks, on the servient lot or parcel;
       2. (B) Agreeing not to put that portion of the servient lot or parcel to a conflicting use; and
       3. (C) Agreeing, upon severance of the lots or parcels, to grant or reserve and record a utility easement and covenant against conflicting uses, in a form DEQ approves, in favor of the owner of the lot or parcel served by the system under paragraph (a) of this section.
12. (12) Initial and replacement absorption area. Except as provided in specific rules, the absorption area, including installed system and replacement area, must not be subject to activity that is likely, in the opinion of the agent, to adversely affect the soil or the functioning of the system. This may include but is not limited to vehicular traffic, covering the area with asphalt or concrete, filling, cutting, or other soil modification.
13. (13) Construction. An agent may limit the time period during which a system can be constructed to ensure that soil conditions, weather, groundwater, or other conditions do not adversely affect the reliability of the system.

14. (14) Permit requirements:

    1. (a) A person may not cause or allow constructing, altering, or repairing a system or any part of one without a WPCF permit issued under OAR 340-071-0162 or a construction- installation, alteration, or repair permit under OAR 340-071-0160, 340-071-0210, and 340-071-0215 except for emergency repairs authorized under OAR 340-071-0215(2) and (3);

    2. (b) The following systems must be constructed and operated under a renewable WPCF permit issued pursuant to OAR 340-071-0162:

       1. (A) Any system or combination of systems located on the same property or serving the same facility and having a total design capacity greater than 2,500 gpd. Flows from single-family residences or equivalent flows on separate systems incidental to the purpose of the large system or combination of systems (e.g., caretaker residence for a mobile home park) need not be included;
       2. (B) A system of any size, if the septic tank effluent produced is greater than residential strength wastewater as defined in OAR 340-071-0100 or systems using pretreatment methods other than grease traps and grease interceptor tanks to achieve residential strength wastewater;
       3. (C) Except as provided for in section (15)(d) of this rule, other systems that are not described in this division and do not discharge to surface public waters or the ground surface.

15. (15) WPCF permits for existing facilities:

    1. (a) The owner of an existing system required to have a WPCF permit under subsection (14)(b) of this rule is not required to obtain a WPCF permit until a system major repair or major alteration of a system, or facility expansion, is necessary;

    2. (b) The permittee of an existing aerobic treatment unit, recirculating gravel filter, commercial sand filter, or alternative treatment technology system constructed or operating under a WPCF permit that is no longer required under section (14) of this rule may request DEQ to terminate the permit:

       1. (A) The permittee must submit, on a DEQ-approved form:

          1. (i) A copy of the service contract required in OAR 340-071-0132; and
          2. (ii) A written statement from a maintenance provider certifying that the system is not failing.
       2. (B) DEQ will send a letter to the permittee to terminate a WPCF permit. The letter will be deemed a Certificate of Satisfactory Completion for the permitted system.
    3. (c) DEQ may terminate WPCF permits for existing holding tanks for which permits are no longer required under section (14) of this rule. DEQ will send a letter to the permittee to terminate the permit. The letter will be deemed a Certificate of Satisfactory Completion for the permitted system;

    4. (d) Permittees of other existing systems or combination of systems constructed or operating under a WPCF permit may request DEQ terminate the permit if all of the following conditions are met:

       1. (A) The system or combination of systems located on the same property or serving the same facility must have a total design capacity of 2,500 gpd or less; and
       2. (B) The system or combination of systems must not produce septic tank effluent greater than residential strength wastewater as defined in OAR 340-071-100; and
       3. (C) The system or combination of systems must have been operating under a WPCF permit before July 1, 2007; and
       4. (D) The absorption facility is described in this division and does not discharge to surface public waters or the ground surface; and
       5. (E) DEQ determines that the system or combination of systems is in compliance with the waste disposal limitations specified in the WPCF permit; and
       6. (F) The permittee submits a copy of a service contract that meets the requirements of OAR 340-071-0132 and
       7. (G) The permittee submits a written statement from a maintenance provider certifying that the system is not failing;
       8. (H) Owners of and maintenance providers for these systems must operate and maintain the system under the requirements described for recirculating gravel filter systems in OAR 340-071-0132 and 0302. DEQ will send a letter to the permittee to terminate the WPCF permit. The letter will be deemed a Certificate of Satisfactory Completion for the permitted system. Conditions specified in the Certificate of Satisfactory Completion continue in force as long as the system is in use.
16. (16) Fees for systems under WPCF permits. Permittees of onsite systems under WPCF permits must pay the annual compliance determination fee in OAR 340-071-0140(4) by the date DEQ specifies for each year the system is in operation.

17. (17) Engineering plan review. Unless specifically exempted in this division, all plans and specifications for constructing, installing, or modifying onsite systems must be submitted to the agent for approval or denial. The design criteria and rules governing the plan review are as follows:

    1. (a) The agent must review all plans and specifications for WPCF permits under OAR chapter 340, division 052;
    2. (b) Plans and specifications for construction-installation permits for commercial sand filter, recirculating gravel filter, and advanced treatment technology systems with design capacities greater than 600 gpd must be signed by a person registered under ORS 672 or 700.

18. (18) Criteria and standards for design and construction. The criteria and standards for design and construction in this division and OAR chapter 340, division 073 apply to all onsite systems:

    1. (a) For onsite systems subject to WPCF onsite permits, DEQ may allow variations of the criteria, standards, and technologies in this division and OAR chapter 340, division 073 based on adequate documentation of successful operation of the proposed technology or design. The system designer must demonstrate the performance of new processes, treatment systems, and technologies under OAR chapter 340, division 052;
    2. (b) For systems not requiring WPCF permits, DEQ may authorize variances from the criteria, standards, and technologies in this division through the variance processes in OAR 340-071-0415 through 340-071-0445.
19. (19) Manufacturer's specifications. All materials and equipment, including but not limited to tanks, pipe, fittings, solvents, pumps, controls, and valves, must be installed, constructed, operated, and maintained under manufacturer's specifications.

20. (20) Sewer and water lines. Effluent sewer and water line piping constructed of materials that are approved for use within a building, as defined by the Oregon State Plumbing Specialty Code, may be run in the same trench. Effluent sewer pipe of material not approved for use in a building must not be run or laid in the same trench as water pipe unless both of the following conditions are met:

    1. (a) The bottom of the water pipe at all points is at least 12 inches above the top of the sewer pipe;
    2. (b) The water pipe is placed on a solid shelf excavated at one side of the common trench with a minimum clear horizontal distance of at least 12 inches from the sewer pipe.
21. (21) Septage management. A person may not dispose of wastewater, septage, or sewage-contaminated materials in any location or manner not authorized by DEQ.
22. (22) Groundwater levels. All groundwater levels must be predicted using conditions associated with saturation. In areas where conditions associated with saturation do not occur or are inconclusive, such as in soil with rapid or very rapid permeability, predictions of the high level of the water table must be based on an agent’s past recorded observations. If such observations have not been made or are inconclusive, the application must be denied until observations can be made. Groundwater level observations must be made during the period of the year in which high groundwater normally occurs in an area. A properly installed nest of piezometers or other methods DEQ accepts must be used for making water table observations.

23. (23) A person may not submit information required by statute, rule, permit, or order that is false, inaccurate, or incomplete.

    [ED. NOTE: All tables are found in OAR 340-071-0800.Publications referenced are available from the agency.]

Statutory/Other Authority

ORS 454.625 & 468.020

Statutes/Other Implemented

ORS 454.615, 454.655, 454.695, 468B.050, 468B.055 & 468B.080

History

DEQ 29-2025, amend filed 10/01/2025, effective 01/01/2026
DEQ 33-2017, minor correction filed 12/11/2017, effective 12/11/2017
DEQ 15-2017, amend filed 10/31/2017, effective 11/01/2017
DEQ 14-2013, f. 12-20-13, cert. ef. 1-2-14
DEQ 5-2007, f. & cert. ef. 7-3-07
DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05
DEQ 14-2000, f. & cert. ef. 8-24-00
DEQ 5-2000(Temp), f. 2-24-00, cert. ef. 3-1-00 thru 8-27-00
DEQ 16-1999, f. & cert. ef. 12-29-99
DEQ 8-1998, f. & cert. ef. 6-5-98
DEQ 12-1997, f. & cert. ef. 6-19-97
DEQ 27-1994, f. & cert. ef. 11-15-94
DEQ 9-1984, f. & ef. 5-29-84
DEQ 8-1983, f. & ef. 5-25-83
DEQ 5-1982, f. & ef. 3-9-82
DEQ 10-1981, f. & ef. 3-20-81