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West Point Treatment Plant
Find information and facts about West Point Treatment Plant located next to Discovery Park in Seattle, including the treatment process, capital and improvement projects, and ongoing public engagement.
November 28, 2025
West Point Lighthouse Beach parking lot closed as King County wastewater operators respond to equipment issue
King County Wastewater Treatment Division is responding to intermittent flooding in the parking lot at West Point Lighthouse Beach in Seattle. This water is fully treated and disinfected from West Point Treatment Plant and is normally released through the plant’s outfall, located 3,600 feet offshore at a depth of about 230 feet in Puget Sound.
Initial investigation shows that a problem with an air-relief valve on the effluent pipeline is causing water to spill out from an underground vault for about three hours during high tide.
The parking lot at West Point Lighthouse Beach is closed while crews investigate and make repairs.
You may see King County staff working in the area. For everyone’s safety, please do not approach them. If you have questions, please call our Community Services hotline at 206-296-7432.
We have notified the regulatory agencies and Seattle Parks and Recreation.
We will share updates and any safety guidance from Public Health-Seattle and King County at kingcounty.gov/WTD-Incident-Response as more information becomes available.
Located next to Discovery Park in Seattle, West Point Treatment Plant (West Point) began operating in 1966. West Point cleans more wastewater each day than any other plant in Washington. Approximately 90 million gallons of wastewater per day are treated at the facility during the dry months. Seattle’s combined stormwater/wastewater sewer system also flows into West Point. West Point serves homes and businesses in Seattle, Shoreline, north Lake Washington, north King County, and parts of south Snohomish County.
Learn more
- Learn how West Point's treatment process works.
- Get the facts on the West Point's operations.
- Discover how West Point contributes to a sustainable future for the surrounding community and environment.