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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

Project Update

Night work planned for Friday, October 10
King County contractors plan to work from 11 p.m. on Friday, October 10 to 3 a.m. on Saturday, October 11 in order to inspect two pipes that will be upgraded during this project. The work will occur in manholes on Lincoln Park Way and in Lowman Beach Park.

The inspection has to occur at night when the pipes are least full and tides are low.
Please direct any concerns or inquiries during work hours to the project hotline: 206-205-9186. The hotline will be the best resource for contacting the project team during the night work hours.

View the construction update (PDF, October 9, 2014) and news release (October 9, 2014).

Saturday work begins October 11
To keep the project on schedule and avoid digging during heavy rains, King County’s contractor will work Saturdays in October (beginning October 11). Saturday work will begin at 9 a.m. and finish at 6 p.m.
View Project Update (PDF, October 1, 2014)

Murray CSO Control Project Information Session
Saturday, October 11, 2014
10 a.m. to 2 p.m.
Lowman Beach Park

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 (external link), 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