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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

December 3, 2024

Project-wide updates

Check out our 2024 newsletter for an overview of this year’s progress and upcoming work. This newsletter is available in English, Español (Spanish), 中文 (Chinese, Simplified), and 正體字 (Chinese, Traditional).

Read the newsletter here to learn more

Crews have been approved to work extended Saturday work hours from 7 am to 7 pm in parts of the project area. Check out our June notification for more information.

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. 

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.

Area 2. North-central Mercer residential streets: Crews are doing pipe repair work on 78th Avenue Southeast between Southeast 22nd Place and Southeast 24th Street doing pipe repair work. For more information about construction impacts and detour routes, check out the October 18, 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 now 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:

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 structures 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. Fruitland Landing park is closed while crews continue to upgrade Lift Station 11.

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.

I-90 trail: As construction continues on northeast Mercer Island, I-90 trail users should follow posted detour routes off the I-90 bridge trail. This takes trail users on East Mercer Way, Southeast 36th Street, and North Mercer Way. Trail users will then be able to connect back onto the I-90 trail. Drivers, please drive slowly and watch for cyclists on the roadway.

Mercer Island Boat Launch: Crews have completed work to install a sidewalk ramp on the east side of Frontage Road near the boat launch.

For more information, check past Area 6 updates.

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: Crews began restoring the shoreline along Enatai Beach Park under the I-90 bridge in late July. Crews continue to work on pipes and structures near the swim beach and under the I-90 bridge. For more information, check out the July Area 7 notification.

Area 8. Sweyolocken/Mercer Slough: The Sweyolocken boat launch and Mercer Slough connector trail is open for community use. Paving and restoration activities are complete. 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

Map showing North Mercer Island/Enatai Sewer Upgrade project area by project status. This includes four miles of pipe across north Mercer Island, upgrading the North Mercer Pump Station and Lift Station 11 at Fruitland Landing, and relining pipes along southwest Bellevue between Enatai Beach Park and the Mercer Slough. Areas are noted as planned construction in yellow line with black outline, active construction in orange dotted line, and post-construction restoration in blue solid line 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 December 1, 2024

Previous general project updates

Project location

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