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Project description

King County is replacing sewer pipes that serve areas in North Mercer Island, the southwest portion of Bellevue near Enatai Beach Park, 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. Once installed, the new pipes will provide sewer service for 50 years or more. To learn more about the project overall, including what we are building, construction information, and what to expect, view our StoryMap.

To meet community needs, we broke the project up into 8 project areas, shown on the map. We provide updates about specific areas depending on where work is taking place.

Map of 8 project areas, starting from the North Mercer Island Pump Station extending eastward to Enatai in Bellevue.

General project updates

July 17, 2024

Project-wide Updates: Extended Saturday work hours from 7 a.m. to 7 p.m. will begin in parts of the project area as early as June 29. These extended hours are expected to be in place through August. Check out our recent notification for more information.

Construction activity in Mercer Island*

Area 1. North Mercer Pump Station: Crews are connecting pump station utilities to the existing water pipe on S.E. 22nd St. This work includes potholing the road, so single lane traffic is in place on S.E. 22nd St. Single lane traffic is expected to be in place during work hours through July 26. Check out our recent notification for more information.

Area 2. North-central Mercer residential streets: Gasket  repair work continues on 78th Ave Southeast and Southeast 24th Street through July 26. 
Expect single-lane traffic with flaggers on 78th Ave S.E., near the S.E. 22nd Pl intersection, and on S.E. 24th St, near the 80th Ave S.E. intersection until the repair work is complete.
Please use caution when driving through the work area and follow all signage and directions from the crew. Check out our recent notification for more details.

Area 3. North Mercer Way: Check our past Area 3 updates here.

Area 4. I-90 Trail: The I-90 trail is closed for pipe installation between Southeast 26th Street and Shorewood Drive and between Southeast 35th Street and Southeast 35th Place. For more information please review our recent Area 4 updates.

Click here for the trail detour map between S.E. 26th St and Shorewood Dr.

Click here for the trail detour map between S.E. 35th St and S.E. 35th Pl.

Area 5. 90th Pl S.E.: Paving on Shorewood Drive and the lower section of 90th Pl S.E. is complete. Check our past Area 5 updates here.

Area 6. NE Mercer Island:

Overnight work at East Mercer Way onramp to I-90 Westbound to load large equipment planned for July 18, 11 p.m. - 4 a.m. Check out our recent notification for more information.

The phase 4 temporary access road detour is ending soon. While crews continue to install pipe on S.E. 35th Pl, residents will have access to and from their homes through East Mercer Way. Temporary restoration of S.E. 35th Pl is planned for the end of summer.

As construction activity near East Mercer Way and S.E. 35th Pl. continues, I-90 trail users should continue following our trail detour route off the I-90 bridge trail. Drivers, please drive slowly and watch for cyclists on the roadway.

Single lane traffic on 96th Ave S.E. continues. Please follow flaggers and traffic signs when driving through the area. Pipe installation on 97th Ave S.E. will begin as early as July 22. Check out our recent notification for more details.

Luther Burbank Park: Construction equipment moved out of the South Parking Lot on May 15. This parking lot is now fully reopen for public use.  

Construction activity in Bellevue*

Area 7. Enatai Beach Park/Lake Washington’s East Channel: Parking and pathways reopen for public use for the summer as construction continues at Enatai Beach Park. For more details, check out our recent notification.

Single lane traffic on 108th Ave. S.E. near S.E. 34th St as PSE continues work on electrical conduits. Check out our recent notification for more details.

Area 8. Sweyolocken/Mercer Slough: The Sweyolocken boat launch and Mercer Slough connector trail is now open for community use! Expect continued construction activities in the area. For more details, check out our recent notification.

Construction status

Click for larger view.

This map is updated as construction progresses across north Mercer Island and southwest Bellevue. It shows areas of planned construction, active construction, and post-construction restoration.

If you need this map in another format, please leave a voicemail on the project hotline at 425-305-3578 or call TTY Relay 7-1-1. Reasonable accommodations are available to you for free.

Map current as of July 1, 2024

Previous general project updates

Project location