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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

May 14, 2015 Update

King County contractors will start replacing a sewer pipe and water pipe in Beach Drive S.W. on Friday, May 15. Crews will use concrete saws, excavators, trucks and a crane to install the new pipes. This work will take about 10 days.

To replace the sewer pipe, crews will cut through Beach Dr. S.W. which can be noisy. There will also be no parking and traffic delays of up to 15 minutes on Beach Drive S.W. from 7 a.m. to 6 p.m. Flaggers will guide traffic around the work site. Local and emergency access will be maintained. Steel plates will be placed over the trench in the street to allow passage over the work area outside of work hours.

View construction update (PDF, May 14, 2015)

April 6, 2015 Update

King County contractors have completed the outer wall and floor of the underground storage tank. Crews are now working on building the tank’s inner walls. This work requires small concrete pours every week. These pours are weather dependent and will last until June 2015.

In order to keep the project on schedule, the contractor may continue working on some Saturdays. Work hours on Saturdays are 9 a.m. to 5 p.m.

View construction update (PDF, April 3, 2015).


Learn more:  What to expect during concrete pours (Winter 2015)

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 overview
View construction schedule overview (PDF) and project meeting calendar.

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

For more information