Skip to main content
King County logo

Project updates

May 2018

Learn about the project

Project description

King County has selected a contractor for this project. Work is expected to begin in April of this year and be completed by December. The project will include: 

  • Construction of access roads in the Lake Hills park to reach the project work areas
  • Dewater operations where sewage flows are directed around where rehabilitation will be taking place in the pipes
  • Repair of corroded sections of the pipeline using a trenchless, below-ground construction method called ‘cured in place pipe’ lining 

(See ‘What does the project include?’ for more details.)

This project is a part of King County Wastewater Treatment Division’s Pipeline Corrosion Rehabilitation Program. We have selected to rehabilitate this line because it is less expensive and has fewer surface construction impacts when compared to building new replacement pipelines.

Why is King County rehabilitating the Eastgate Interceptor Pipeline in the Lake Hills Greenbelt Park?

The Eastgate Interceptor pipeline is a part of King County’s regional wastewater system. Pipelines carry wastewater from homes and businesses to our regional treatment plants.

The Eastgate line is about six miles long and consists of two parallel pipes. The first pipe was built in 1963, and the second pipe was added in 1983 to add capacity. A section of this sewer line runs through the Lake Hills Greenbelt in Bellevue.

Both pipes are ageing and reaching the end of their service life. Substantial corrosion has been detected in the pipes, including the section which runs through the greenbelt. If these portions of the pipes are not fixed, the pipes could fail, which could disrupt service and result in wastewater overflows.

In order to protect the community and the environment, King County is planning to rehabilitate both pipes along a 2,400 foot-long section of the Eastgate line. This project will extent the useful life of this pipeline another 50 years.

Project area

Download map and map with aerial background .

Project work areas and access road

King County will be using a pipe lining method called ‘cured in place pipe’ lining, or CIPP. This involves inserting a resin-coated liner into the pipes at manholes. The liner is rolled out and inflated to take the shape of the pipe. The liner is then cured with hot water to harden it in place.

The pipes need to be dry during lining, so a temporary ‘bypass’ pipe will be used during construction to carry wastewater around this section of the pipe.

The work in Lake Hills Greenbelt Park is expected to begin in early 2018 and take eight to nine months to complete. Two other lining projects along other sections of the Eastgate line have already been completed.

King County will build temporary access roads and work pads around the existing manholes within the park. The work will take place within some areas of the community Pea Patch and the Master Gardener’s demonstration garden, near the ranger station and along parts of the Lake to Lake trail which runs through the park. The trail will be open most of the time during construction, though there will be short periods when the trail is closed to move construction vehicles and equipment.

  • Access roads, staging and work in parts of the park & garden areas
  • Noise, odors, some tree and vegetation removal
  • Short-term and intermittent closures of the “Lake to Lake” trail to move construction equipment
  • Temporarily construction impacts to some park uses, activities, and programs
  • Construction traffic delays and disruptions on Southeast 16th Street
  • Temporary use of portions of the Lake Hills Greenbelt parking areas off Southeast 16th Street

King County will restore all affected areas, including the demonstration and pea patch gardens, trails, and wetlands within the park. The County will replace trees and vegetation that were removed, and restore these areas to an equivalent state as it currently exists.

Project timeline

The work in Lake Hills Greenbelt Park is expected to begin in early 2018 and take eight to nine months to complete.

Being a good neighbor

King County is committed to being a good neighbor and will work directly with the community throughout the project to minimize construction impacts whenever possible. We will send out additional project information and schedules when available. Residents can expect:

  • Advance notice of construction activities—by mail, email, phone, door hangers
  • Project construction updates
  • Project construction phone and email so you can easily contact county staff about the project

Stay informed and sign up for project updates

We welcome hearing from you if you have questions or comments about the project. This summer, we will be holding an open house so people can learn more about the project. Contact us if you are interested in attending the open house or in signing up to get construction updates.


For information about the project

Sign up for project email or text updates (or manage your King County subscriptions).

For questions about the project, contact David Freed at: or at 206-263-9453

Project location

Locator map for Eastgate Interceptor rehabilitation (lining) - Phase 3

Back to the capital projects overview map .

Sewer pipe liner being inserted at a manhole on the County's Beach Drive lining project in West SeattleSewer pipe liner being inserted at a manhole on the county’s Beach Drive lining project in West Seattle.