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Project update

January 2022

Pre-construction survey

Alignment of the pipeline work along North Mercer Island (North Mercer Pump Station) to Enatai (Sweyolocken Pump Station).  Construction is starting soon, and we want to hear from you! A pre-construction survey will arrive in project area mailboxes in early January. We want to hear from neighbors before construction to ensure that we know how best to reach you about construction activities. We also want to be sure that we have heard from you before construction if you have concerns.

Thank you in advance for taking the time to fill out this survey. The paper copy can be mailed back with the instructions on the mailer. Or fill it out online at The survey deadline is February 8.

If you are interested in a project update for your community group or neighborhood, please contact Kristine Cramer at 206-477-5415 or

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.

nme_construction_reference_guideConstruction Reference Guide.


Project design began in 2016 and will be complete in 2021. Construction is expected to begin in 2021 and extend until 2025.

project timelineView larger version .


Contact us

Contact Kristine Cramer, community services lead at:

 Feedback form

24-hour construction hotline: 206-263-1915

Sign up for email or text updates

To sign up for email and text updates, please visit the construction page.

Project location

Project pipeline alignment and service area

Back to the capital projects overview map .

Lets Talk Mercer Island!

Construction is expected to start later this year on the Mercer Enatai Sewer Upgrade. The City of Mercer Island and King County are collaborating to ensure Mercer Island residents get timely, accurate construction information. In addition to the County’s website, Let’s Talk Mercer Island will feature the project as it moves into construction.

We will provide monthly updates on Let’s Talk, and we will monitor the site for resident questions and comments. And of course, as always, don’t hesitate to reach out directly with any questions or concerns you might have.

Related information

Regional Wastewater Services Plan

Local municipalities: