North Mercer Island/Enatai sewer upgrade

General project updates

December 20, 2024

Project-wide updates

Construction is underway across north Mercer Island and southwest Bellevue. To keep everyone safe, follow all instructions from crews and signage and use caution as you travel through work areas. 

King County’s contractor has been approved to continue working extended Saturday work hours from 7 am to 7 pm in project areas on north Mercer Island. These extended hours began in June 2024 and are now approved through March 29, 2025. For more information, check out our December project-wide notification.

Construction activity in Mercer Island*

Area 1. North Mercer Pump Station: Crews continue work to upgrade the existing pump station on S.E. 22nd Street. This includes work on the generator building, surge tank, and electrical systems. Crews constructed a temporary pump station to keep wastewater flows moving during these important upgrades.

Area 2. North-central Mercer residential streets: Crews are repairing pipes on 78th Avenue Southeast between Southeast 22nd Place and Southeast 24th Street. Single-lane traffic and temporary traffic control signals are in place on 78th Ave S.E. Crews need to continue working in this area through early 2025. For more information about construction impacts and detour routes, check out the December 2024 Area 2 notification.

Area 3. North Mercer Way: Crews installed pipe and paved North Mercer Way in 2023 and installed accessible curb ramps in spring 2024. For more information, check out past Area 3 updates.

Area 4. I-90 Trail: The I-90 trail between Southeast 26th Street and Shorewood Drive is open!

The I-90 trail remains closed between Southeast 35th Street/North Mercer Way and Southeast 35th Place/East Mercer Way for sewer construction in the area. Trail users should follow the posted detour route:

• Trail detour map between S.E. 35th St and S.E. 35th Pl. This takes trail users on East Mercer Way, Southeast 36th Street, and North Mercer Way, before connecting back to the I-90 trail. Drivers, please drive slowly and watch for cyclists on the roadway.

For more information, check past Area 4 updates.

Area 5. 90th Pl S.E.: Paving on 90th Pl S.E. is complete. Crews continue work on the odor control structure in the cul-de-sac at the top of 90th Pl S.E. For more information, check past Area 5 updates.

Area 6. NE Mercer Island:

S.E. 36th St near City Hall:  Crews completed utility potholing work on Southeast 36th Street near City Hall.

Fruitland Landing: Crews are preparing to reline the existing pipe on 97th Ave S.E. north of S.E. 34th St. Neighbors may notice additional equipment in the area, but noise and vibrations are not expected to increase. We will provide an update with more details on what to expect when relining work is scheduled. Please use caution while traveling over steel plates in the roadway. Fruitland Landing park remains closed while crews upgrade Lift Station 11 and upgrade the pipes in the roadway.

S.E. 35th Pl: Crews have installed an air vent line in the roadway on East Mercer Way at S.E. 35th Pl. The intersection has been temporarily paved is now open to two-way vehicle traffic. For more information, check out the November Area 6 notice.

Mercer Island Boat Launch: Crews have completed work to install a sidewalk ramp on the east side of Frontage Road near the boat launch. The parking lot is open for community use.

For more information, check past Area 6 updates.

Luther Burbank Park: In late November, King County’s contractor moved construction equipment into the back half of the South Parking Lot at Luther Burbank Park. Equipment storage is permitted until May 15. The front half of the parking lot remains open for community use.

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Construction activity in Bellevue*

Area 7. Enatai Beach Park/Lake Washington’s East Channel: Crews continue to work on pipes and structures near the swim beach and under the I-90 bridge. Both parking lots as well as the swim beach, dock, and playground are all open for community use. For more information, check out past Area 7 updates.

Area 8. Sweyolocken/Mercer Slough: The Sweyolocken boat launch and Mercer Slough connector trail is open for community use. Crews are in the area to work on structures near the Sweyolocken Pump Station. For more information, check out past Area 8 updates.

* Construction schedules can change based on factors such as site conditions, weather, and material availability. Please check this website for updates.

Construction status

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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 December 1, 2024