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Project update

December 28, 2018

As early as January 3: utility locating, potholing, and survey work will begin on North Mercer Island. This work will last up to four weeks.

December 13, 2018

Field investigations near Bellevue shoreline, Enatai Beach Park, and Sweyolocken Pump Station – will be resuming in early 2019.

King County Wastewater Treatment Division is continuing field investigations to inform design of a sewer upgrade project in Mercer Island and Bellevue. Originally expected to be complete in mid-December, work has been rescheduled for early next year. Crews will conduct potholing and survey work to identify existing utilities near the project route. Crews will also work in Enatai Beach Park and at Sweyolocken pump station to confirm locations of existing utilities. King County will notify property owners ahead of any work on private property.

181120_field-work-locationsSee Dec. 28 project update to learn more.

If you or someone in your community would like to learn more about the project, please contact Kristine Cramer, or 206-477-5415 to schedule a briefing.

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.

Project area mapView larger version . December 2018


Project design began in 2016 and will be complete in early 2020. Construction is expected to begin in 2020 and extend until 2024.

project timeline View larger version .

Project location


Back to the capital projects overview map .

Related information

Regional Wastewater Services Plan

Local municipalities: