North Mercer Island/Enatai sewer upgrade

General project updates

May 19, 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 August 30, 2025. For more information, check out our March project-wide notification.

Join us for exciting summer engagement events! Our community relations team will have information tables set for this year’s Bike Everywhere Day and Summer Celebration events. Stop by to grab a snack, score some swag, and dive into all things project related. For more information, check out our May 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 14, crews will be completing on-site training at the pump station. While neighbors may notice an increased number of contractor vehicles in the area, noise and vibrations will remain at levels typical of an active construction site. No additional impacts are expected.

Testing for the new fire alarm system in the pump station building has been postponed. We will provide an update when the work has been rescheduled. Neighbors near the pump station can expect periodic noise and lights from the pump station building while testing is in progress. For more information, check out the February Area 1 notification.

Area 2. North-central Mercer residential streets: King County's contractor has begun pipe repair work on North Mercer Way, between 80th Avenue Southeast and Island Crest Way. To ensure safety, road closures are in place on North Mercer Way between 80th Ave S.E. and Island Crest Way and at 81st Ave Southeast and North Mercer Way. Residential access will be maintained during this work. Please travel slowly through the area and follow all signs, traffic control signals, and directions from crews. For more information, please review our May 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: Repairs between 84th Avenue Southeast and Shorewood Drive are now complete, and community access to this section of trail has been restored. The section of trail between Fortuna Drive and Southeast 35th Street remains closed while crews work to safely complete the remaining pipe repairs. Work is expected to continue through May, and this section of trail will reopen once repair work is finished. Please follow the posted trail detour route along North Mercer Way. Drivers should use extreme caution while moving through this area. For more information, check out the May 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.

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:

Fruitland Landing: Crews continue working on improvements to Lift Station 11 at Fruitland Landing and are preparing to begin pipe relining work later this year. We will provide an update when we have more details about the schedule and impacts for this work. For more information, check out our May Area 6 notification.

S.E. 35th Pl: Crews continue to work on Southeast 35th Place. Additional construction, including odor control work, water tie-in, and final repaving, is planned for this year. We will provide updates as soon as the work is scheduled and we have more information.

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: 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:

East Channel: Drone surveying to support East Channel substrate monitoring is complete. Crews continue to restore the shoreline in the East Channel. We will provide an update when restoration has been completed.

Enatai Beach Park: 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

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 February 1, 2025