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Project update

January 2022

Read more about the Lake Hills sewer relining project in this fact sheet .

No in-person events

Due to COVID-19, King County’s Wastewater Treatment Division is not currently hosting in-person meeting or events. However, we are committed to sharing information in alternative ways.

Our staff remain available to answer questions via email and phone. We can also:

  • Join your virtual meeting
  • Provide virtual briefings for community groups
  • Send you information in the mail about this project

Let us know how we can best communicate with you and your community by contacting Eunice Lee at 206-263-1614 or

The Lake Hills Sewer Relining Project is part of King County Wastewater Treatment Division’s Pipeline Corrosion Rehabilitation Program.

Why is King County rehabilitating the Lake Hills sewer pipe?

The Lake Hills Interceptor is a sewer pipe that collects and carries wastewater from homes and businesses in Bellevue to the South Treatment Plant in Renton for treatment.

Now over 50 years old, the Lake Hills sewer pipe is experiencing corrosion, and needs to be relined so it does not fail, overflow, or disrupt service. To protect the community and the environment, King County is planning to rehabilitate a 7,200-foot-long section of the pipe. This project will extend the useful life of this pipeline for another 50 years.

We have selected to rehabilitate instead of replace this sewer pipe because it is less expensive and has fewer surface construction impacts when compared to building new replacement pipes

What are the benefits?

  • Extend the useful life of the pipe for another 50 years
  • Maintain reliable service for our customers
  • Improve water quality in our region

Project description

As part of the project, King County will install pipe lining along approximately 7,200 feet of the 48-inch and 54-inch diameter concrete pipe. We are currently exploring different ways to do this relining work, but we plan to repair the pipe in its current placement in order to minimize impacts during construction.

The pipes need to be dry during lining, so we will need to reroute existing wastewater into a smaller temporary pipe. This temporary pipe would likely be routed above ground along streets, partially trenched, or be outfitted with ramps to help people and vehicles safely travel across. We are currently working to determine where the temporary pipe will be located during construction that is planned to begin in 2023. Construction is expected to take up to six months.

Learn more below about how we extend the life of our pipes by lining them:

What temporary impacts can you expect during construction?

Construction impacts will likely include lane closures, detours, and equipment staging along the project area. Additional impacts may include noise and odors from the diversion pumps. This project may include overnight work. We will share more details as plans develop and will keep the community informed.


This project will have multiple phases:
2021: We are currently in the predesign phase of this project. During predesign, we will:
  • Decide what methods we will use to reline the pipe
  • Determine the location of the temporary pipe, which will carry wastewater during the relining project
  • Identify impacts on the surrounding community
Spring 2022 – Spring 2023: Next year, we will begin designing the project. During this phase, we will:
  • Design the temporary pipe
  • Determine what permits are needed
  • Communicate plans with impacted neighbors and the surrounding community
Spring – Fall 2023: We will begin project construction in the dry season (May-October) of 2023. During construction, we will:
  • Prepare the site for construction
  • Install the temporary pipe
  • Line the pipe in place
  • Restore and clean up from construction
  • Provide updates to impacted neighbors and the surrounding community

Planning Phase

Contact us

Contact Eunice Lee at:

If you’d like to receive email or text updates on the Lake Hills sewer relining project:

Project location

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