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For questions about the Wastewater Treatment Division Web site, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 505
Seattle, WA 98104-3855
Phone: 206-684-1280
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Get Directions to our office location in Seattle, Washington.

Staff Contacts

Puget Sound shoreline next to the West Point Treatment Plant, Seattle

King County Wastewater Discharge Permits
from municipal wastewater facilities

King County discharges treated wastewater under permits issued by the Washington State Department of Ecology (Ecology). Ecology administers the National Pollutant Discharge Elimination System (NPDES) permits (external link) under authority delegated to the department by the U.S. Environmental Protection Agency. These permits outline the conditions under which a municipality can discharge treated wastewater. Learn more about Wastewater Discharge Permits in Washington State (PDF, external link).

King County has four NPDES permits for discharging treated wastewater from its regional wastewater system:

NPDES Permit Description

Permit no. and expiration date

Download permit*

West Point Treatment Plant, Seattle, WAThe West Point permit covers the operation of the West Point Treatment Plant in Seattle, the combined sewer overflow (CSO) system, the CSO treatment facilities including Alki, Carkeek, Elliott West, Henderson/Martin Luther King, and the portion of the conveyance system owned by King County.

WA-002918-1
June 30, 2014

(Ecology Web site)
Permit;
Fact Sheet;
Responsiveness Summary for comments received on Draft Permit  

South Treatment Plant, Renton WAThe South Plant permit covers the operation of the South Treatment Plant in Renton and the portion of the conveyance system owned by King County.

WA-002958-1
Sept. 30, 2009

(Ecology Web site)
Permit;
Fact Sheet;
Appendices

Carnation Treatment Plant, 2009The Carnation Treatment Plant permit covers the operation of the Carnation Treatment Plant and the portion of the conveyance system owned by King County.

WA-003218-2
April 15, 2013

(Ecology Web site)
Permit;
Fact Sheet

Vashon Treatment Plant, Vashon Island, WAThe Vashon Treatment Plant permit covers the operation of the Vashon Treatment Plant and the portion of the conveyance system owned by King County.

WA-002252-7
Aug. 31, 2011

(Ecology Web site)
Permit;
Fact Sheet

Note: Also covered under these permits is the Industrial Pretreatment Program administered by King County. That program is responsible for approving permits for discharges of industrial waste into the sewer system and the management and enforcement of such permits.

* Requires a PDF Reader to view document. If link doesn't work, refer to Ecology's list of permits by NorthWest region at: http://www.ecy.wa.gov/programs/wq/permits/northwest_permits.html

News releases

Other NPDES permits held by King County

Other permited activities include the following:

  • Production and distribution of reclaimed water at the South Treatment Plant Water Reclamation Facility (permit, appendix, fact sheet--Adobe Acrobat files available for download from the Ecology Web site)
  • Operation of the Beulah Park/Cove community wastewater treatment system on Vashon Island: permit, fact sheet (permit, fact sheet, fact sheet addendum--Adobe Acrobat files available for download from the Ecology Web site)
  • Municipal stormwater permits.

Other county resources and information

For more information

  • Please contact Wastewater Treatment Division NPDES Administrator Betsy Cooper at 206-263-3728.