North Mercer Island/Enatai sewer upgrade

General project updates

April 29, 2026

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 June 27, 2026. For more information, check out our August 2025 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: As early as May 5, crews will perform final milling and paving on SE 22nd St. Work will start on one side of the road and shift to the other side. Roads will be single lane alternating traffic. Access for residents and vehicles will be maintained. After permitted work hours, the road will reopen to two-way traffic. For more information, please review our April Area 1 and 2 notification.

Area 2. North-central Mercer residential streets: As early as May 5, crews will perform final milling and paving on SE 22nd St, 78th Ave SE, SE 24th Street, and 81st Ave. Work will start on one side of the road and shift to the other side. Roads will be single lane alternating traffic. Access for residents and vehicles will be maintained. After permitted work hours, the road will reopen to two-way traffic. For more information, please review our April Area 1 and 2 notification.

Area 3. North Mercer Way: no updates.

Area 4. I-90 Trail: As early as May 5, crews will perform final milling and paving sections of the I-90 trail by Shorewood Drive, and in a second section of the trail between Island Crest Way and 84th Avenue Southeast  Until the trail reopens, please follow all detour signs and travel slowly around the work area. For more information, please review our April Area 4 notification.

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.

Area 4. N Mercer Way by Fortuna Dr: As early as May 5, crews will grind the roadway on N Mercer Way by Fortuna Dr for final milling and paving. Access to Covenant Shores will be maintained. After permitted work hours, the road will reopen to two-way traffic. For more information, please review our April Area 4 notification specific to this work.

For more information, check past Area 4 updates.

Area 5. 90th Pl S.E.: Crews are continuing restoration and testing of the odor control unit in the cul-de-sac at the top of 90th Place Southeast. Crews will return to pave a small area behind the odor control unit during the next permitted paving window, which begins in Mid-March. For more information, check past Area 5 updates.

Area 6. NE Mercer Island: 

S.E. 36th St near City Hall: Crews are working on the 96th Avenue siphon, a sewer pipe that runs under I-90. Crews are accessing the underground pipe at two locations. Work at the intersection of 96th Avenue Southeast and Southeast 35th Street is expected to take approximately three months to complete. Work on Southeast 36th Street in front of Mercer Island City Hall is expected to take approximately four months to complete. Single lane alternating traffic is in place on Southeast 36th Street for construction work. Please travel slowly through the area and follow all posted signs and crew directions. For more information, please review our March Area 6 notification.

Fruitland Landing: As early as May 5, crews will be performing final milling and paving on 97th Ave SE for paving work. Work will start on one side of the road and shift to the other side. Roads will be single lane alternating traffic. Access for residents and vehicles will be maintained. After permitted work hours, the road will reopen to two-way traffic. For more information, please review our April Area 6 notification.

S.E. 35th Pl: Crews completed grinding and temporary paving on Southeast 35th Place and Frontage Road. Restoration work in this area continues.

For more information, check past Area 6 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.

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Construction activity in Bellevue*

Area 7. Enatai Beach Park: Crews are continuing restoration and testing work within the fenced area at Enatai Beach Park. 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 February 1, 2025