King Street Regulator Station Overflow Sediment Remediation Project

The King Street Regulator Station (RS) Overflow is identified under the County's 1999 Sediment Management Plan as needing cleanup. The plan evaluated remediation strategies for correcting hazards caused by contaminated sediments near seven King County combined sewer overflows (CSOs).

The remediation will be completed as a coordinated multi-agency project that includes WSDOT (Coleman Dock and Pier 48 projects) and the City of Seattle (Washington St. CSO/storm drain).

King Street Regulator Station Overflow

Wastewater from the King St. Regulator Station flows through the Elliott Bay Interceptor (EBI) east of the Lower Duwamish Waterway to the West Point Treatment Plant. During heavy storms, excess wastewater flows are sent to Elliott Bay via the King St. CSO outfall. Improved system efficiencies have reduced the need to discharge untreated wastewater through the outfall. In addition, King County plans to build a new 151-million gallon per day (MGD) wet weather treatment facility to control the King St. and Kingdome CSOs into Elliott Bay and the Lander and Hanford CSOs into the East Waterway. The facility’s outfall may be located in either Elliott Bay or the East Waterway. The project is scheduled to be completed by 2030.