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Wastewater Treatment

King County, Washington

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

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-477-5371
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Get Directions to our office location in Seattle, Washington.

Staff Contacts

Protecting Puget Sound

kayak on the water 

King County's Wastewater Treatment Division protects Puget Sound water quality by treating on average over 170 million gallons of wastewater produced by residents and businesses each day. King County is a member of the Puget Sound Partnership (external link), which is coordinating a comprehensive plan to protect and restore the Sound ecosystem by 2020. Protecting Puget Sound requires action from all of us: governments, businesses, and citizens. The Sound is affected by choices we make and how we live and work. There are many things all of us can do to protect and restore Puget Sound. WTD continues to develop and implement programs to improve wastewater quality and to protect our most precious resource:

  • Public education helps citizens understand wastewater treatment and make smart choices to protect wastewater quality.
  • The Industrial Waste Program works to improve wastewater quality by regulating industrial discharges to the regional wastewater system and providing customers with technical assistance.
  • The Combined Sewer Overflow Control Program works to control temporary storm-related overflows in areas where stormwater and wastewater systems are combined, and provide public notification when CSOs occur.
  • Sediment Management Program coordinates clean up of sediment contamination near county outfalls for combined sewer overflow facilities in Seattle, and works with partners such as Boeing, the Port of Seattle, and the City of Seattle in areas affected by historical pollution.
  • Using reclaimed water at and near existing facilities and  planning for the future provides opportunities to manage wastewater effluent.
  • Construction projects upgrade and replace aging infrastructure to provide safe, reliable service. Expanding existing facilities and building new ones provides enough capacity for the region's growing population, insuring continued protection of Puget Sound.
  • King County's Marine and Sediment Assessment Group supports a comprehensive, long-term marine monitoring program that assesses water quality in the Central Puget Sound Basin on behalf of, and in coordination with, the King County Wastewater Treatment Division. Water quality data and reports are available from the monitoring program.
  • King County's Environmental Laboratory supports WTD by providing quality field, laboratory, information technology, and advisory services and responding to water quality emergencies in King County.

Related information

King County wastewater treatment plants

Of interest