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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

Capital improvement projects

Learn more about system and project phases of King County projects

In 2016, King County to invest $196.8 million in capital projects to expand the wastewater system, modernize existing facilities, and ensure continued compliance with environmental laws. View February 4 news release.

Specific projects are included in the list below.

King County is carrying out these projects as part of the Regional Wastewater Services Plan, a 30-year comprehensive plan adopted by the King County Council in 1999 to ensure the regional sewer system keeps pace with growth and continues meeting regulatory requirements.

Murray Combined Sewer Overflow Control Project

Projects by area Learn more
North King County/South Snohomish
East King County
South King County
Project phases and public involvement 
Planning for growth
Being a good neighbor during construction
Enhancing the environment with our facilities
Recently completed projects