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Completed Spring 2020

Wastewater Treatment Division (WTD) operations and projects

WTD operations staff remain on the job 24/7 to ensure the region’s wastewater treatment service continues. More information on how to report a problem you believe may be related to the County’s wastewater treatment system is available here:

The King County Wastewater Treatment Division remains committed to sharing information and gathering feedback from community members about its work and projects. WTD staff remain available to answer questions via email and phone during regular business hours. Project information lines remain available and are being monitored for ongoing construction projects.

Project updates

The repaired pipeline became operational in November 2019. Restoration and final project completion are expected in the Spring of 2020. View final project update (March 4, 2020).

Project description

The Eastside Interceptor (ESI) is a regional sewer line that carries wastewater from eastside homes and businesses to King County’s South Treatment Plant in Renton. This project repaired approximately 3,700 feet of the line by installing a liner on the walls of the pipe.

The project followed Logan Avenue North, from around the intersection of Garden Avenue (The Landing Shopping Center) on the north end, to near North 6th Street between Logan and Burnett Avenue North at the south end of the project. View project area map .

Project schedule

Work began in the spring of 2019 and the pipeline became operational in November 2019. Project restoration should be complete in the Spring of 2020.

Why did we need this project?

The Eastside Interceptor is one of the main sewer lines that bring untreated wastewater to the treatment plant in Renton. This line starts near Kirkland and runs south on the east side of Lake Washington. It is eight feet in diameter by the time it gets to the project area. The pipe is aging and was reaching the end of its service life. It is over 50 years old and corrosion was found in parts of the pipe. The pipe needed to be repaired so it does not fail, overflow or disrupt service.

What are the benefits?

This project will allow the pipe to stay to be used for at least 50 additional years. The pipe lining approach reduced the surface impacts compared to replacing the line.


For information about the project

For questions about the project, contact Eunice Lee at:

Project location

project area mapProject area map

An intake pit bordered by metal shoring with temporary pipes traveling up from the main pipeline.The excavated intake pit allows crews to prepare for diverting water from the pipe in preparation for pipe lining.

A crew member in a high visibility vest watches as the bypass pipe is lowered into place with a crane.The bypass pipe is assembled from separate pieces and lowered into place using a crane.

A large bypass pipe runs along a road. A concrete border and cones are installed to guide traffic while work is underway.The bypass pipe is installed along a road. A concrete border and cones are used to guide traffic while work is underway.

A plastic pipe is routed from a maintenance access hole and runs towards an industrial fan with a carbon scrubber. This set-up ensures odor control and ventilation along the pipe length are safe for crews to work inside.Odor control and ventilation along the pipe length ensure the conditions in the pipe are safe for crews to work inside.

A white lining material is attached to the inside of the pipe.The pipe interior after it has been lined with the protective material.

Learn how King County repairs and protects pipes from degradation using a technique called “lining.” See the above- and below-ground processes used to apply an adhesive liner to the sewer pipe’s interior and to keep crews working inside the safe.

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