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Project update

January 4, 2018

Survey work on Mercer Island January 8-12; Expect delays along North Mercer Way

King County Wastewater Treatment Division is continuing field investigations to inform design of a sewer upgrade project in Mercer Island and Bellevue. In December, crews completed potholes to locate underground utilities including gas, sewer, power, water and telecommunication lines. Now, crews will return to pothole locations to conduct survey work. This work will confirm the horizontal and vertical location of specific utilities along the alignment.


What you can expect:

  • Flaggers will direct vehicle and pedestrian traffic around the work site, as necessary.
  • Bike path access will be maintained.
  • Work hours 7:30 a.m. to 3:30 p.m. Monday to Friday.
  • Each location will take approximately one hour to complete.
  • All work is expected to be complete by January 12, depending on field conditions.
  • Survey crews will use a tripod and handheld survey equipment at each location.   

For additional information, see the latest project update .

Sign up for email or text updates

To sign up for text alerts, text KING MERCERSEWER to 468-311 for Mercer Island, and KING ENATAISEWER to 468-311 for Enatai. To sign up for email updates, please visit the public involvement page.


Contact us

Contact Kristine Cramer, community services lead at:


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Project description

With over 400 miles of pipes moving wastewater to one of our award-winning treatment plants, King County WTD works hard to maintain our system. We inspect and monitor our regional system and update plans for needed upgrades.

King County WTD needs to replace sewer pipes that serve areas in North Mercer Island, the southwest portion of Bellevue near Enatai Beach, and the Town of Beaux Arts Village . This pipeline carries wastewater from the North Mercer Island Pump Station to the Sweyolocken Pump Station in Bellevue.

1701_NME-final-pipeline-route_700View larger version. July 2017


Project design will begin in 2016. Construction is expected to begin in 2019 and extend until 2022.

Project TimelineClick to view larger version .

Project location


Back to the capital projects overview map .

Related information

Regional Wastewater Services Plan

Local municipalities: