Vashon Treatment Plant
9615 SW 171st St.,
Vashon, Washington
Welcome to the Vashon Treatment Plant, located at 9615 SW 171st St., on Vashon Island in Puget Sound southwest of Seattle, Washington.
The plant serves the Vashon Sewer District as part of King County's regional system that treats wastewater for about 1.4 million people in the Puget Sound region. The collection system, owned and maintained by the Vashon Sewer District, delivers sewage to the plant from about 425 residential and commercial customers in and around the island's main business area.