Kent-Auburn conveyance system improvement

New regional wastewater facilities to serve the growing population

As part of its 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 regional wastewater facilities to serve the growing population. The county provides 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 conveys it to the county's South Treatment Plant in Renton. The population in the south portion of the 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. The new pipelines will provide service and operational flexibility to handle population growth in south King County.

Project Status

King County has selected preferred alignments for the new pipelines and is moving into final design for the Phase A projects (Stuck River Trunk and Kent East Hill Diversion). In final design, these alignments will be more thoroughly analyzed and developed. In addition, the county will focus on environmental review, applying for the appropriate permits and preparing construction bid documents.

The Phase B projects (Pacific Pump Station Discharge and Auburn West Interceptor Parallel) are also moving forward in the design process. The project team will continue to work with local jurisdictions, regulatory agencies, property owners and neighbors to gather feedback during design and in anticipation of construction.

View the project overview page for the anticipated schedule.