North Mercer Way
Construction on North Mercer Way will take about two months. Sign up for updates to receive the start date when it's available.
This StoryMap focuses on the work being done on North Mercer Way. To learn more about the Mercer Enatai Sewer Upgrade project as a whole, visit the project website .
The blue line on the map shows the new sewer pipeline. King County is also upgrading the North Mercer Pump Station and the City of Mercer Island's Lift Station 11.
What are we building?
King County is installing approximately four miles of new sewer pipe across north Mercer Island and Southwest Bellevue. Some of the new pipe will be installed underneath streets, including a short stretch of North Mercer Way between the Park and Ride and Island Crest Way.
The new sewer line mainly follows non-arterial streets. However, there will be a 500 foot segment of pipe under North Mercer Way just east of the Mercer Island Park and Ride.
King County tried to avoid work on North Mercer Way due to its heavy use, but working in this short stretch of road was unavoidable.
This image shows the pipeline as it runs under North Mercer Way and crosses Island Crest Way to the I-90 trail.
What to expect
Construction is disruptive. Everyone who lives or travels on streets under construction will be impacted by the work.
We will send out alerts so you can plan ahead if you live near the active work area.
Crews will use a construction technique called “open-cut” trenching to bury the pipe where it needs to go. During open-cut construction, crews dig a trench. Then they lay the pipe in the trench, attach it to existing pipe, fill in the trench, and restore the surface.
Open cut construction
This image shows a trench box holding back soil so workers can install pipes. On North Mercer Way, the trench will be approximately eight feet wide.
Like any construction project, there will be noise, dust, traffic impacts and other inconveniences.
- North Mercer Way will remain closed during this construction segment.
- Permitted weekday work hours are 7 a.m. to 7 p.m. We will provide advance notification of any weekend or after hours work.
- Traffic will be detoured around North Mercer Way.
- Metro buses will be routed through the detour routes.
Mercer Isle Condo
- Residents of the Mercer Isle Condo building will have access to the condo on SE 24th Street.
- The driveway that exits onto North Mercer Way will be accessible for condo residents except for a short period of time when construction is directly in front of the driveway.
- Mercer Isle Condo will continue to have service and mail delivery at its usual locations.
Schedule and duration
Construction on the overall sewer upgrade is underway and will last into 2025. As part of this, we expect this stretch of North Mercer Way to be closed for about two months.
We will provide advance notification for this work on our website and by email once it is available. Please sign up to stay up to date about the work and schedule related to this section of the project.
Vehicle detour routes
The detour routes shown here are subject to final approval by the City of Mercer Island.
Car detour route from the I-90 Westbound ramp to Mercer Park and Ride
Car detour route while crews lay pipe from from Mercer Isle condo driveway exit to Island Crest Way.
Vehicles exiting the I-90 off ramp will be directed north or south around North Mercer Way.
Car detour route while crews lay pipe across Island Crest way to the I-90 Trail.
While crews lay pipe across Island Crest Way to the I-90 Trail, vehicles exiting I-90 Westbound will be directed south toward Town Center or straight on North Mercer Way toward the Park and Ride. We will not block driveways on SE 26th Street.
Bicycle and pedestrian detour routes
The detour routes shown here are subject to final approval by the City of Mercer Island.
This map shows the detour route for bicycles and pedestrians while crews lay pipe under North Mercer Way is south on Island Crest Way or 80th Ave SE.
Bicycles will merge with vehicles and pedestrians will use the designated pedestrian paths. Bicycles can choose to dismount and walk the pedestrian path.
This map shows the detour route for bicycles and pedestrians while crews lay pipe from the Mercer Isle condominium driveway to Island Crest Way.
Bicycles will travel on streets and the I-90 trail connector. Pedestrians will stay on pedestrian paths, including the I-90 trail connector.
This map shows the detour route for bicycles and pedestrians while crews lay pipe across Island Crest Way to connect it to the I-90 Trail is south on Island Crest Way to the I-90 connector trail.
What you'll see when the work is done
King County will repave impacted impacts, including North Mercer Way and a small portion of Island Crest Way, after construction.
When open cut construction is complete, we will restore disturbed areas based on permit conditions agreed upon with the City of Mercer Island and other regulatory agencies.
Some restoration work, such as paving streets and planting vegetation, is best done during certain seasons. This could mean a gap in time between the end of construction and when restoration occurs.
How to reach us
We are committed to working with you during construction.
Here is what you can expect:
- Signs at the Mercer Park and Ride with information about this closure.
- Regular web updates.
- Email and/or text announcements - sign up on our webpage.
- Quick resolution of problems and concerns.
- Call or email us . We will get back to you within one business if it is not an emergency. If it is a project-related emergency, we will get back to you right away.
Talk to us!
For more information or to schedule a virtual meeting, contact the Community Relations Team:
- 425-306-3578
- NMEsewer@kingcounty.gov
Learn more
Visit the project webpage to learn more and sign up for email and/or text alerts: www.kingcounty.gov/MercerEnataiSewer
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