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On-Site Sewage Disposal Permit

(More than 100,000 gallons per day)
Description/Purpose

Businesses and residences that locate outside areas served by sewer systems often treat and dispose of sanitary sewage through nearby septic tanks and subsurface drain fields. The purpose of this permit is to control discharges so that they do not degrade ground water or surface water quality.

In some rural areas, industrial and commercial operations may use on-site systems for treatment and disposal of process wastewater, as opposed to or in addition to residential-strength domestic wastewater (sewage). Ecology is the only agency with jurisdiction over this discharge and may require state discharge permits for either domestic or industrial/commercial on-site systems.

For more information on state discharge permits for domestic systems, see http://apps.oria.wa.gov/permithandbook/permitdetail/20.

For more information on state discharge permits for industrial/commercial systems, see https://fortress.wa.gov/ecy/publications/summarypages/ecy040178.html.

Ecology generally requires public ownership, operation, and maintenance of domestic wastewater (sewage) facilities.

Triggers and activities which would require this permit

Large On-site Sewage Systems with any of the following characteristics require coverage under this permit:

  • A design flow exceeding 100,000 gallons per day;
  • Systems whose discharge includes industrial/commercial process wastewater or stormwater;
  • Systems that discharge to the land surface (such as wetlands or infiltration lagoons without a drainfield); or
  • Systems that discharge to surface water (including those that discharge to ground, where groundwater is in hydraulic continuity with surface water).
Explanation/Description of costs/fees, including statutory, regulatory, or other legal authority for fees

There is both an application fee and a coverage fee for this permit; both vary depending on the permit specifications. The fee schedule can be found under WAC173-224.

Application Information

The application is called 'Application for a Wastewater Discharge Permit for Discharge of Municipal Wastewater to Groundwater' is online and can be accessed at https://fortress.wa.gov/ecy/publications/SummaryPages/ecy040178.html.

The design of a large on-site sewage disposal system is first approved by Ecology under WAC 173-240. The applicant must then apply for the Large On-Site Sewage Disposal System Permit for operation of the system under WAC 173-216. When making the decision on your permit, Ecology will consider the applicable laws and rules, the contents of your application, and the background environmental conditions.

The permit is good for 5 years.

You have a right to appeal this permit coverage to the Pollution Control Hearings Board (PCHB) within 30 days of issuance of this general permit.

The appeal process is governed by Chapter 43.21B RCW, Chapter 173-226 WAC, and Chapter 371-08 WAC. “Date of receipt” is defined in RCW 43.21B.001(2).

To appeal you must do both of the following within 30 days after the date of receipt of issuance of this general permit:

  • File your appeal and a copy of the permit cover page with the Pollution Control Hearings Board (PCHB) during regular business hours.
  • Serve a copy of your appeal and the permit cover page on Ecology in paper form, by mail or in person. E-mail is not accepted.
Legal authority
Notes / Comments

For an overview of the permitting process, see the on-line publication Wastewater Discharge Permits in Washington State.

Contacts
Local Government - City or County
Planning Departments
Website: http://mrsc.org/Research-Tools.aspx
Comment: Please contact the appropriate local authority for more information. Contact information may be found at Local Counties.
Department of Ecology
Headquarters
300 Desmond Drive
PO Box 47600
Olympia WA 98504-7600
Website: http://www.ecology.wa.gov/
Telephone: (360) 407-6000
Department of Ecology, Northwest Regional Office
Dawn Marie Maurer
3190 - 160th Avenue SE
Bellevue WA 98008-5453
Website: http://www.ecology.wa.gov/
Telephone: (425) 649-7000
Fax: (425) 649-7098
Department of Ecology, Southwest Regional Office
300 Desmond Drive
PO Box 47775
Olympia WA 98504-7775
Website: http://www.ecology.wa.gov/
Telephone: (360) 407-6300
Fax: (360) 407-6305
Department of Ecology, Central Regional Office
15 West Yakima Avenue, Suite #200
Yakima WA 98902-3452
Website: http://www.ecology.wa.gov/
Telephone: (509) 575-2490
Fax: (509) 575-2809
Department of Ecology, Eastern Regional Office
4601 N Monroe
Spokane WA 99205-1295
Website: http://www.ecology.wa.gov/
Telephone: (509) 329-3400
Fax: (509) 329-3529
* Credential details last updated 8/21/2023
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