1. (1) Permit required. A person may not alter or increase the design capacity of an existing onsite wastewater treatment system not under a WPCF permit without first obtaining an alteration permit under this rule or a construction-installation permit under OAR 340-071-0160, as applicable. The permit application procedure is described in OAR 340-071-0160.

2. (2) An agent may issue an alteration permit if the requirements of either paragraph (a) or (b) of this section are met.

   1. (a) Alterations do not increase the system's design capacity and:

      1. (A) The existing system is not failing;
      2. (B) The site setbacks in Table 1 can be met except that if the setbacks in Table 1 for septic tanks, treatment units, effluent sewers, and distribution units cannot be met, the agent may allow a reasonable installation; and
      3. (C) In the agent’s opinion, use of the onsite system would not create a public health hazard or result in water pollution.

   2. (b) Alterations do not exceed the existing system design capacity by more than 300 gpd or 50 percent, and:

      1. (A) The existing system is not failing;
      2. (B) The setbacks in Table 1 can be met; and
      3. (C) In the agent’s opinion, using the onsite system would not create a public health hazard or result in water pollution.
3. (3) An application for a construction-installation permit under OAR 340-071-0160 is required when the existing system design capacity is proposed to be exceeded by more than 300 gpd or more than 50 percent.

4. (4) Certificate of Satisfactory Completion required. Upon completing installation of that part of a system for which a permit was issued, the system installer must comply with the requirements for pre-cover inspections in OAR 340-071-0170. The agent must issue or deny the Certificate of Satisfactory Completion for the completed construction under OAR 340-071-0175. The projected daily sewage flow into the system may not be increased until the Certificate is issued.

   [ED. NOTE: All tables are found in OAR 340-071-0800.]

Statutory/Other Authority

ORS 454.625 & 468.020

Statutes/Other Implemented

ORS 454.615, 454.655, 454.665 & 454.675

History

DEQ 29-2025, amend filed 10/01/2025, effective 01/01/2026
DEQ 42-2017, minor correction filed 12/14/2017, effective 12/14/2017
DEQ 15-2017, amend filed 10/31/2017, effective 11/01/2017
DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05
DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95
DEQ 8-1983, f. & ef. 5-25-83
DEQ 10-1981, f. & ef. 3-20-81