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This survey is about the accessibility of our products, programs, services, and spaces. Please complete the survey by September 30, 2026: here. WTD will use the information shared with us to help identify and prioritize steps to make our system more accessible for all people.
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 update
September 2026
Surveying starts in Redmond this fall. Temporary lane closures will begin as early as September 28
Crews will check wetland and soil conditions. They will also confirm the location of existing or new utilities. Surveying will take place throughout the full project area.
Construction planned to begin in 2029
We will continue to gather information, work with nearby property owners, and finalize our project designs until we start construction.
Interested in a project briefing for your community group?
We are happy to meet with you or come to your next community event. We can share the latest project information and answer questions you might have as we get closer to construction. Please contact Annie Plumley at 206-263-3203 or LakeHillsSewerUpgrade@kingcounty.gov for more information.
Previous project updates
- Tree surveying starts July 6; Meet us at Derby Days on July 25, June 2026
- Join us in person for Bike Everywhere Day on May 13!, May 2026
- Summer is right around the corner! Join us at summer 2025 community events!, May 2025
- Continuing work in 2025, January 2025
- Summer comes to a close: summer 2024 outreach recap, September 2024
- Designing large sewer upgrades take time... Construction now expected to begin in 2026, July 1, 2024
- Project update, August 23, 2023
- Survey work along 177th Ave NE starting as early as May 8, May 2023
- Construction expected to begin in 2024, Spring 2022
- Fieldwork along sewer alignment scheduled to begin the week of March 21, March 21, 2022
- Delays and increased congestion on and near West Lake Sammamish Parkway beginning as early as November 1, October 28, 2021
- Summer 2021 Project Newsletter, August 2021
- Expect delays and increased congestion on and near West Lake Sammamish Parkway beginning as early as August 31, August 28
- Summer 2020 Project Newsletter, August 2020
- Expect delays and increased congestion on and near West Lake Sammamish Parkway starting as early as July 13, July 8, 2020
- Fall 2019 Project Newsletter, October 2019
- Join us at Bike Everywhere Day on May 17! May 10, 2019
- Catch up on our design process and read about what's next!, August 2018
- Join us at Bike Everywhere Day on May 18! May 11, 2018
- Expect short delays on West Lake Sammamish Parkway and residential streets beginning March 20, March 14, 2018
- Online Open House archive (December 2017 - January 2018), February 6, 2018
- Stop by the online open house to review and comment on the latest project designs! December 5, 2017
- Final design for the Lake Hills and NW Lake Sammamish Sewer Upgrade Project begins, November 2017
- Join us for drop-in sessions in November! November 1, 2017
- Expect increased noise and activity in Luke McRedmond Landing starting as early as Oct. 16, October 9, 2017
- Soil sampling in ravine scheduled to begin as early as September 7, August 31, 2017
- Soil sampling on 180th Ave. N.E. continues September 6, August 29, 2017
- Contractor moving to Sammamish River Trail this week. Sampling on West Lake Sammamish Parkway complete, August 15, 2017
- Soil samples begin on 180th Avenue August 14, August 9, 2017
- Soil samples continue August 7 on West Lake Sammamish Parkway, August 2, 2017
- Expect lane and sidewalk closures, short delays on West Lake Sammamish Parkway and local roadways starting as early as July 31, July 27, 2017
- Soil samples starting July 31 on West Lake Sammamish Parkway and 177th Ave NE, July 27, 2017
- Sammamish River in-water survey work north of the Leary Way Bridge week of July 5, June 28, 2017
- Expect short roadway and trail delays during utility investigations starting as early as Monday, April 24, April 18, 2017
- Fieldwork efforts nearing completion – alignment for new sewer pipe to be finalized in early 2017, November 29, 2016
- Geotechnical work this week, WTD's GoGreen booth a hit, and Pokemon, don't Go here! July 25, 2016
- Geotechnical work begins June 23 in Idylwood for King County’s sewer upgrade project in Redmond, June 22, 2016
- Project update, June 8, 2016
- Project update, February 2016
- Project news, January 2016
- King County touring your area, April 24, 2015
Project description
King County will replace 4.5 miles of sewer pipes in Redmond and Bellevue. These pipes are more than 50 years old. The new pipes will support the growing community. This regional sewer upgrade will keep service safe and reliable for many years in the future.
If you live or work on the northwest side of Lake Sammamish, these sewer pipes serve you every day. The dirty water you make goes into these pipes. Then it travels to Brightwater Treatment Plant near Woodinville! First, the water you send down the drain moves through private pipes. Then, it flows into the local sewer system. The local sewer system connects to King County’s larger regional sewer pipes. These regional pipes deliver dirty water to King County’s regional treatment plants. The treatment plants clean the water and send it safely to Puget Sound.