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Project update

March 1, 2018

The online open house is live! Stop by to review the detailed sewer upgrade route

The online open house for North Mercer/Enatai Sewer Upgrade Project will be open until March 31, 2018.

Be sure to stop by to review:

  • Detailed maps of the sewer upgrade route
  • What we know now about construction
  • Next steps for project design
  • How we will work with you throughout the project

A comment form is available for you to ask questions and share your feedback on how King County can be a good neighbor.

Reminder: Walk-and-talks this Saturday

Our team will be walking residential streets on Saturday, March 3 in Mercer Island to discuss the detailed route with neighbors and answer questions about what to expect during construction. Additional information about this event, including times and meeting locations, is available on our meeting calendar.

Field investigations continue in Mercer Island and Bellevue

King County Wastewater Treatment Division is continuing field investigations to inform design of a sewer upgrade project in Mercer Island and Bellevue. Crews began taking soil sampling, ground surveys and potholing in late January and will continue through March.

Crews taking soil samples, ground surveys and potholing.

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:


 Feedback form

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: