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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

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Staff Contacts

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

Project Construction

August 8, 2016 update:

Starting as early as Monday, Aug. 8, King County’s contractor will use a concrete saw to cut through the roadway on Beach Dr. S.W. at the intersection with 48th Ave S.W. The saw will cut thin lines in the road in preparation for road restoration. You will still be able to drive on the road after it has been cut. Saw cutting is expected to take three to five days to complete.

What to expect:

  • Beach Dr. S.W. narrowed to one lane at the intersection with 48th Ave S.W.
  • Increased noise levels
  • Traffic delays of up to five minutes
  • Flaggers safely directing traffic through the intersection during working hours
  • Variable roadway conditions. Cyclists should use caution when traveling through the intersection

Additional project work will continue while saw cutting is underway.

Thank you for your continued patience during construction.

Please direct any questions or concerns to the project hotline: 206-205-9186. .

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