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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

Murray CSO control project -- Building a new storage tank to protect Puget Sound

Project Construction

July 25, 2016 update:

King County’s contractor for the Murray CSO Control Project has finished installing the five-foot-wide sewer line under Beach Dr. S.W. Starting as early as Saturday, July 23, the contractor will begin installing the connection pipe between the new five-foot-wide pipe, the underground storage tank, and the local sewer service line. This work will take approximately one month to complete.

Please see the July 22nd project update (pdf) for more information about this work.

Thank you for your continued patience during construction. Please contact the project hotline: 206-205-9186 with any questions or concerns.

Have a comment or question? Need more information about the project? 
Click here to contact the project team.

Murray Project Hotline: 206-205-9186

Learn more about Final Facility Design
Final Design
, December 2012

Haul routes
Project haul routes
, February 2014

Murray basin and project location
Murray basin and project location

Project description

King County is designing an underground storage tank across the street from Seattle’s Lowman Beach Park. The tank will store approximately one million gallons when the Murray Pump Station exceeds maximum capacity.

Why do we need this project?

Protect public health

Like many cities around the country, the older parts of King County's wastewater system uses a single set of pipes to carry untreated sewage and stormwater to a treatment plant. To prevent sewer backups into homes and streets, the system includes safety valves called “combined sewer overflows” that route excess sewage and polluted stormwater flow directly into Puget Sound during storms. Although CSOs reduce potential exposure to untreated sewage, they pose significant public health concerns.

Clean up Puget Sound

The Murray CSO control facility will reduce CSOs into Puget Sound. State regulations require no more than one untreated discharge per year. The Murray Pump Station averages five untreated CSO events per year, discharging 5 million gallons into Puget Sound off of Lowman Beach Park.

Project schedule

Construction schedule

How has the community shaped facility design?

Since October 2011 Lowman Beach Park neighbors and park users have worked with local designers, environmentalists and community advocates to help the King County project team design a facility that fits with the community. These discussions produced “common themes” for the design that reflect the community’s values for a safe, reliable facility. The common themes are:

  • Minimize the “industrial facility” feel
  • Encourage views of Puget Sound
  • Discourage through traffic on Beach Drive
  • Enhance continuous space between Lowman Beach park and the facility site

Southbound vehicles on Beach Drive SW can use the access road south of the park to turn around
Southbound vehicles on Beach Drive SW can use the access road south of the park to turn around.

Have a question or concern? Please use the project feedback form.

Project updates

Find out if a CSO is occurring in Murray

Related information

  • To learn more about the Project Planning Phase (CSO control alternatives selection process in the Murray basin, 2007 to 2010), please see the Facility Plan.
  • Protecting Our Waters (Combined Sewer Overflow Control Program), King County 

For more information

This project is funded in part by:

Department of Ecology, State of Washington