Water Treatment Plants General Permit - NPDES Waste Discharge

What is the purpose of this permit?
This general permit ensures that the settled backwash effluent discharged from water treatment plants (WTPs) to the surface waters of Washington State causes no harm to water quality or to the environment.
Who issues this permit?
Department of Ecology
What activities require this permit?
All WTPs that discharge backwash effluent to surface water and that meet all of the following conditions must obtain coverage:
  • Produce potable water or "industrial" water (primary treatment/settled water) where the treatment and distribution of water is the primary function of the facility.

  • Have an actual production rate equal to or greater than 35,000 gallons per day of treated product water (finished water) as determined on an average monthly basis. "Actual production rate" is the amount of finished water that a treatment facility actually produces on any given day. To calculate the value of the actual production rate on an average monthly basis, add the value of each daily production rate during a calendar month, and divide the sum by the total number of days in the month. The Washington State Department of Ecology reserves the right to determine that permit coverage is needed for facilities with actual production rates less than 35,000 gallons per day in order to protect water quality.

  • The wastewater discharge is from water treatment filtration processes (filter backwash, sedimentation/pre-sedimentation basin washdown, sedimentation/clarification, or filter-to-waste).

  • The water treatment works are not part of a larger, permitted facility, such as a pulp and paper mill.
How much will this permit cost?
Ecology does not charge an application fee for this General Permit. However, there is a coverage fee, which as of 2016, cost $3,403 annually, up to $3.00 per residential equivalent for those WTPs that serve primarily residential customers. The number of residential equivalents is determined by dividing the facility's annual gross revenue in the previous calendar year by the annual user charge for a single-family residence that uses 900 cubic feet of water per month. For current fee rates, see http://apps.leg.wa.gov/wac/default.aspx?cite=173-224-040
Where can I get the application for this permit?
The application is online and can be accessed at https://ecology.wa.gov/Regulations-Permits/Permits-certifications/Water-treatment-plants.
Do I need to include anything with my application?
You must also include a Site Sketch, as an electronic "pdf" or "jpg" attachment. Ecology may request additional information or have questions after reviewing the application form.
Is the decision on my permit dependent on anything besides the information in my application?
When making the decision on your order/permit, Ecology will consider the applicable laws and rules, the contents of your application, and the background environmental conditions.
How long will it take to review my application?
WAC 173-226-200 and RCW 90.48.170: Application for permits shall be made at least 180 days prior to commencement of any proposed discharge or permit expiration date, whichever is applicable. See the Permit Timeliness Results above for average processing times.
Where do I submit my application?
The application is submitted electronically via the Water Quality Permitting Portal at https://secureaccess.wa.gov/ecy/wqwebportal/or to the appropriate Ecology Regional Office. Find and contact the appropriate regional office or call the statewide contact noted below. Logging into your SecureAccess Washington account is required at https://SecureAccess.wa.gov. Use the Department of Ecology "Water Quality Permitting Portal" service.
How long is my permit valid?
Your General Permit is valid for up to 5 years. Coverage for a facility begins at time of application approval and ends when the General Permit expires or your coverage is revoked. The next term of the Water Treatment Plant General Permit will expire on August 31, 2019. However, Ecology may administratively extend the General Permit past 5 years until the agency has completed the permit renewal process.
What is the appeal process for the permit?
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.
Consideration of an appeal of general permit coverage of an individual discharger is limited to the general permit’s applicability or inapplicability to that individual discharger.
Legal Authority:
Permit Timeliness Results

Permit Timeliness data collection is in response to a State Auditor’s Performance Audit and RCW 43.42A. Each regulatory agency developed a plan to improve permit clarity, predictability, and timeliness. Each agency considers the customers experience to ensure permit assistance is simple to use, easy to access, and designed in a customer-friendly manner. Agencies report progress to the Governor’s Office for Regulatory Innovation and Assistance (ORIA). ORIA prepares and distributes reports, with participation from the State Auditor’s Office and Results Washington. See latest report here: https://www.oria.wa.gov/ORIA-2020-PermitTimelinessProgressReport.pdf.

All permits submitted for reporting were entered into this Regulatory Handbook. Here are the results of the performance data:

Estimated Time Required By the Agency to Process a Permit Application (Definition)
Average number of days from Receipt to Complete: 110
Maximum number of days from Receipt to Complete: 110

Estimated Time Required By the Agency to Issue a Permit Decision (Definition)
Average number of days from Complete Application to Decision: 30
Maximum number of days from Complete Application to Decision: 30

(Summary results based on 1 submittals in 2018, no data for current year)

Where can I get permitting assistance?
Web page URL: https://ecology.wa.gov/Regulations-Permits/Permits-certifications/Water-treatment-plants
Subject matter expert phone: Subject Matter Expert
Department of Ecology
300 Desmond Drive
PO Box 47600
Olympia, WA 98504-7600
Telephone: (360) 407-6000
Website: http://www.ecology.wa.gov/
* Permit information last updated 10/26/2022