Kent-Auburn Conveyance System Improvements Project

New regional wastewater facilities to serve the growing population

As part of our mission to protect public health and the environment, King County is responsible for conveying and treating wastewater collected within the county’s service area. King County is committed to upgrading and improving its regional wastewater facilities to serve the growing population. We provide capacity to support planned growth, consistent with the Washington State Growth Management Act (external link).

Purpose of the project

Wastewater from south King County is collected by local cities and sewer districts, including the cities of Kent, Auburn, Algona, and Pacific. King County collects sewage from these local jurisdictions and carries it to the county’s South Treatment Plant in Renton. The population in the south portion of our service area is growing rapidly. Because of capacity limitations in its existing pipelines (called interceptors and trunks), King County needs to provide additional capacity in the near future.

Constructed improvements will provide capacity to handle the 20-year peak flows through the year 2050. Only those pipes with capacity limitations in the year 2010 will be upgraded as part of this project. Pipes with capacity limitations in the decades after 2010 will be improved when needed. The new pipelines will provide service and operational flexibility to handle population growth in southern King County.

Project Status

We're currently in the planning phase of the project, with engineers still considering project alternatives and looking at basic design requirements. Over the next few months, county staff will begin holding community meetings to give people an opportunity to learn more about the project, ask questions, and make comments on proposed alternatives.

Anticipated project schedule

• Alternatives selection and predesign: Spring-Summer 2007
• Environmental review: Fall 2007
• Design and permitting: Winter 2008
• Construction: Early 2009 - 2010

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Project area

This project involves pipeline improvements in two areas: the Auburn planning area, which includes the cities of Auburn, Algona and Pacific; and the Kent planning area.

Click on the map (right) for an overview of the project areas, moving from north to south.

Your comments and ideas are welcome

King County is committed to being a good neighbor and welcomes your comments. Throughout the project we will work directly with the cities of Kent, Auburn, Algona, and Pacific and the public to ensure that suggestions and concerns are addressed.

King County is evaluating alternative pipeline routes. As we develop alternatives, we will work with local jurisdictions, key stakeholders, and the public to identify potential community and environmental impacts—and ways to minimize them—early in the design process. This work will continue during environmental review, permitting, construction, and long-term operations and maintenance of the facilities.

For more information

For more information or to be added to the project mailing list, please contact Jennifer Kauffman at 206-263-6029 or 711 TTY Relay, or jennifer.kauffman@kingcounty.gov.

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Department of Natural Resources and Parks
Wastewater Treatment Division
201 S. Jackson St.
Seattle, WA 98104-3855
Fax: 206-684-1278

Updated: Sept. 12, 2007

Related Links

Conveyance System Improvement Program

Construction Projects

Local Sewer Agencies

Cities of Algona, Auburn, Kent and Pacific
(external links)