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Lake Hills and NW Lake Sammamish sewer upgrade

The Lake Hills and NW Lake Sammamish Sewer Upgrade Project will upgrade 4.5 miles of sewer pipes serving the growing Redmond and Bellevue area.

Project description

The Lake Hills and NW Lake Sammamish sewer pipe has been serving Redmond and Bellevue for 50 years, carrying wastewater to Brightwater Treatment Plant in Woodinville for treatment. King County is working on a project to upgrade 4.5 miles of this sewer pipe to meet the growing needs of the community. King County will build the new pipe in trails, roads, and parks in Redmond.

Construction on the project is expected to begin in 2026 and may impact your daily routine. When the project is complete, the new pipe will provide sewer service for 50 years or more.

Project update

May 2025

Join us for Bike Everywhere Day on May 14!

Our project team will be hosting booths to celebrate Bike Everywhere Day on Wednesday, May 14. You can find us located along the Sammamish River Trail at two locations throughout the day. From 6-9 a.m. we will be located along the trail near Dudley Carter Park and from 4-7 p.m. we will be located along the trail near the entrance to Marymoor Park. Stop by our booths to learn more about the project and meet a members of our team. We hope to see you there!

Map displaying the booth location from 6-9am (along the trail near Dudley Carter Park) and 4-7pm (along the trail near the entrance to Marymoor Park).

Designing large sewer upgrades take time… Construction now expected to begin in 2027

King County continues to update the design of the sewer upgrade project to meet permitting requirements from the City of Redmond, the City of Bellevue, and several state and federal agencies. Coordination with our partner agencies is necessary to make sure we install the new pipe in the safest way possible, limit impacts and maximize improvements for people and the environment.

Due to a delay in the design and permitting processes, we anticipate construction will begin in 2027. Thank you for your patience while we work hard to finalize our sewer design.

Interested in a project briefing for your community group?

We are happy to meet with you or come to your next community event to share the latest project information and to answer questions you might have as we get closer to construction. Please contact Annie Plumley at 206-263-3203 or aplumley@kingcounty.gov for more information.

Sign up for project text alerts

Be sure to sign up for project updates to stay up-to-date on the latest project information and upcoming events. You can also get updates from your phone. To sign up for text alerts, text KING REDMONDSEWER to 468-311.

Previous project updates

Project location

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