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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

Fall 2024

Looking forward to 2025

We had a great time connecting with our neighbors at various fairs and festivals over the past few months. We want to give a special thank you to all who visited our booth to speak with our project team and learn more about the project. Visit the public engagement page for summaries of each summer outreach event. 

As we look forward to 2025, the project team will finalize design and continue securing local, state and federal permits to prepare for the start of construction.

Two King County staff persons sitting at a table with a green table cloth labeled with "King County Department of Natural Resources and Parks, Wastewater Treatment Division"

Designing large sewer upgrades take time… Construction now expected to begin in 2026

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 2026. 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 Pfeifer at 206-263-3203 or amurrillpfeifer@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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