Education at the Vashon and Carnation Treatment Plant Facilities
Tours at the Vashon and Carnation Plants
Vashon and Carnation Treatment Plant tours are only available to university classes, professional groups, and other adult community groups in a limited capacity, and are subject to staff availability.
Please submit tour requests via the King County Education registration portal.
The Vashon Treatment Plant, located on Vashon Island, treats wastewater from homes and businesses within the Vashon Sewer District.
The Vashon Sewer District contracted with King County in 1999 to take over operation of the Vashon Treatment Plant. King County constructed a new treatment plant (completed in 2006) next to the existing treatment plant.
The Carnation Treatment Plant, located in the City of Carnation, serves about 2,000 people in Carnation’s urban growth area, with capacity to serve up to 4,000 in 2030.
The Carnation Treatment Plant produces reclaimed water that is sent to the nearby Chinook Bend Natural Area for wetland enhancement.