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Wastewater Treatment

King County, Washington

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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

January 8, 2016 Update

Now that much of the 5-foot wide sewer pipe is installed under Beach Dr. S.W., King County’s contractor will begin connecting the pipe to the underground storage tank inside the project site on the east side of Beach Dr. S.W. This work will require the contractor to install additional steel sheets and beams, called shoring. The shoring will hold back water and soil during pipe installation.

Shoring installation for the 5-foot wide pipe will occur intermittently through March 2016 as pipe installation moves east toward the underground tank. Jackhammers and excavators will be used to install shoring causing intermittent, increased noise and vibration, similar to when shoring was installed under Beach Dr. S.W. earlier this fall. King County’s contractor will continue to monitor noise and vibration levels to ensure that levels stay within the limits permitted by the City of Seattle.

Once the 5-foot wide pipe is in place, additional smaller utility lines will be installed under Beach Dr. S.W. Installation of these utilities will continue through spring 2016. Increased noise and vibration levels will continue while shoring is installed for these utilities, but levels will be lower than those expected during shoring installation for the 5-foot wide pipe.

Facility building and additional utility work will continue as described in the Dec. 22 update (PDF). Expect truck traffic, congestion, and traffic delays on streets near the project site while this work is underway. Parking and safety restrictions on the 7000 block of Beach Dr. S.W. remain in place. Please continue to follow the direction of signage and flaggers to stay safe when passing through the site.

Facility on top of storage tank, viewed from southwest (December 2015)
Facility, viewed from south (December 2015)

Facility, viewed from southeast (November 2015) 

What to expect

• Work will continue on weekdays from 7:00 a.m. – 6:00 p.m. and some Saturdays from 9:00 a.m. – 5:00 p.m.
• Crews working in the project site, Lowman Beach Park, and Beach Dr. S.W.
• Truck traffic, congestion, and traffic delays on streets near the project site
• No parking on the 7000 block of Beach Dr. S.W.
• Flaggers and signage in place to direct vehicle, pedestrian, and bicycle traffic on Beach Dr. S.W. and at the intersection with 48th Ave. S.W.

View project update (PDF, December 22, 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

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