North Mercer Island/Enatai sewer upgrade

General project updates

October 27, 2025

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 hours from 7 a.m. to 7 p.m. in all project areas across north Mercer Island. These extended hours began in June 2024 and are now approved through December 27, 2025. For more information, check out our August project-wide notification.

Please note that the texting option on our hotline is not currently available. To connect with us, please call our hotline at 425-305-3578 or email NMESewer@kingcounty.gov.

Construction activity in Mercer Island*

Area 1. North Mercer Pump Station: Crews continue work to upgrade the pump station, including work on the pump station building, the generator building and testing newly installed systems.

Area 2. North-central Mercer residential streets:

• Pipe repair work on Southeast 22nd Place: Crews will be repairing pipe on SE 22nd Pl and 78th Avenue Southeast down SE 22nd St as early as October 27. This work is expected to continue through early November. Traffic control will be in place 24/7, both during and after work hours. For more information, please review our recent October Area 2 notification.
• Paving and restoration: Final paving and restoration activities on Southeast 22nd Street, Southeast 22nd Place, 78th Avenue Southeast, Southeast 24th Street, and 81st Avenue Southeast is postponed. An updated notice will be shared with more details on the timing of the work. For more information, please review our October Area 2 notification.

Area 3. North Mercer Way: no updates.

Area 4. I-90 Trail: The I-90 Trail between Island Crest Way and SE 35th Street is now open for trail users. Crews may occasionally be on site to access maintenance holes for cleaning or testing.

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: no updates

Luther Burbank Park: King County’s contractor has moved construction equipment out of the back half of the South Parking Lot at Luther Burbank Park. The full parking lot is open for community use. 

Construction activity in Bellevue*

Area 7. Enatai Beach Park/Lake Washington’s East Channel: no 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 February 1, 2025