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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

King County wastewater facilities in West Seattle

As part of its mission to protect public health and the environment, King County is responsible for conveying and treating wastewater collected by 34 local city and sewer agencies in the King County region, including the City of Seattle (external link).

Four county pump stations (53rd Avenue, 63rd Avenue, Murray Avenue and Barton Street) located along the Puget Sound shoreline send wastewater flows from the local sewer system through the West Seattle Tunnel to the West Seattle Pump Station. From there, flows are sent to the West Point Treatment Plant, located next to Discovery Park, Seattle. During storm events, some excess flow is treated at the Alki Combined Sewer Overflow (CSO) Treatment Plant.

In the mid-1990s, the West Seattle Pump Station and tunnel were constructed, and the 63rd Avenue Pump Station and Alki CSO Treatment Plant were upgraded to transfer flows to West Point for treatment.

In 2007, initial upgrades (pumps, mechanical and electrical equipment) were made at Murray Avenue Pump Station. Additional upgrades (standby generator and odor control) are planned as part of the Murray CSO Control Facility project.

In 2010, the ageing 53rd Avenue Pump Station was rebuilt and new odor control equipment and standby generator added.

The Barton Street Pump Station is being upgraded in the next few years.

There is also a CSO control project underway to reduce CSOs at the Barton pump station. Learn more about the Barton CSO control (green stormwater infrastructure) project.

West Seattle Facilities Upgrade
View larger version (PDF, 900KB).