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Wastewater Treatment

King County, Washington

For questions about the Wastewater Treatment Division website, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-477-5371
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

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Staff Contacts

Interbay Pump Station upgrade

Project construction

Interbay Pump Station. Click to view more project photos.
The Interbay Pump Station is located near the intersection of West Garfield Street and 15th Avenue West. More photos.
Interbay Pump Station vicinity map
The pump station conveys wastewater flows from the Elliott Bay Interceptor system serving central, south and southwest Seattle to the County’s regional West Point Treatment Plant in Magnolia.

To protect public health and the environment by conveying the region’s wastewater for treatment safely and reliably the King County Wastewater Treatment Division is upgrading the Interbay Pump Station. Many of King County’s wastewater facilities are more than 40 years old and do not meet current design standards.

The Interbay Pump Station, built in 1967, is located near the intersection of West Garfield Street and 15th Avenue West in Seattle. The pump station conveys wastewater flows from the Elliott Bay Interceptor system serving Seattle to the County’s regional West Point Treatment Plant in Magnolia.

Need for the project

The purpose of this project is to replace 1960s era mechanical and electrical equipment, upgrade the HVAC systems, provide standby power generation capacity to power the pumps, provide odor control, and increase overall pump station capacity from 122 million gallons per day (mgd) to 133 mgd. The pump station will remain in operation throughout construction.

View construction photos.

Summary of proposed work

  • Construct new generator building to provide emergency power and improve the pump station’s reliability
  • Replace all three pumps, one each summer (2012, 2013, 2014)
  • Replace/upgrade mechanical, electrical, and controls equipment
  • Upgrade the HVAC systems
  • Increase pump station capacity from 122 mgd to 133 mgd.

Anticipated construction schedule

  • January 2011 – February 2015

Related information

For more information