North Mercer Island/Enatai sewer upgrade
Project update
May 26, 2023
Construction activity in Mercer Island*
At the North Mercer Pump Station: Crews continue pouring concrete for the temporary pump station. See the notification for details and what to expect .
On 90th PL SE: Crews continue installing the new sewer line. See the notification for details and what to expect .
On Shorewood Drive: Crews continue installing the new sewer line. See the notification for details and what to expect .
On SE 35th St: Pipe installation at North Mercer Way and SE 35th St will start as early as May 31. Residential access will be maintained. See the notification for details and what to expect.
On the I-90 Trail: Crews are installing pipe using an “open cut” trenching construction technique. The trail is closed from Shorewood Dr to SE 35th PL. The trail will remain closed around the clock until it has been repaved. Additionally, you may see crews in orange vests preparing for landscape restoration and tree replanting. See the notification for detours and what to expect .
On SE 35th Pl: Crews are preparing to install a new sewer line that will run underneath streets and through the wooded area between 97th Ave SE and the cul-de-sac on SE 35th Pl. To support future operations, below-ground structures are being built in the cul-de-sac. Parking is restricted with resident access maintained. See the notification for details and what to expect .
At the Mercer Island Boat Launch: As early as May 15, we will close a lane of traffic on Frontage Road for construction activities. The boat launch will stay open. Please follow traffic control measures, such as flaggers and signals, and plan for delays. See the notification for details and what to expect .
Additionally, overflow parking for the Mercer Island Boat Launch is available on weekends at City Hall. See the notification for more details .
Construction activity in Bellevue*
At Enatai Beach Park and the Sweyolocken Pump Station: Work continues at Enatai Beach Park and near the Sweyolocken Pump Station. The Mercer Slough connector trail is expected to remain closed through Fall 2023. See the detour map .
Recent notifications:
- Work begins at North Mercer Way and Southeast 35th Street as early as May 31
- Weekend overflow parking for the Mercer Island Boat Launch at City Hall
- North Mercer Way closure began May 15
- Preparation activities beginning at the Mercer Island Boat Launch
- Update: North Mercer Way 60-day closure to begin as early as May 8
- Update: Schedule updates for pipe installation on 90th Pl SE
- Update: North Mercer Way 60-day closure upcoming for pipe installation
Construction status
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Project description
With over four hundred 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.
To learn more about what we are building, construction, and what to expect, click on the StoryMap below.
Schedule
Project design began in 2016 and was completed in 2021. Construction began in early 2022 and will extend until 2025. View March 2022 project newsletter for latest schedule .
Contact us
Contact the community services leads at:
Emily Berry, 206-848-0698
Annie Pfeifer, 206-263-3203
NMEsewer@kingcounty.gov
24-hour construction hotline:
425-305-3578
Project location
Back to the capital projects overview map .
Lets Talk Mercer Island!
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 with monthly updates and will monitor for resident questions and comments.
Related information
Local municipalities: