Sewer workers quickly stop overflow at Vashon Island Treatment Plant

King County’s sewer utility staff quickly stopped a sewage spill that occurred about 1 p.m. when a broken pump valve caused a solids holding tank to overflow at the Vashon Island Treatment Plant.

The county is still investigating the spill volume and the extent of the area affected, though initial assessments indicate that most of it was contained on-site.

As a precautionary measure, King County crews took water samples from nearby Gorsuch Creek and posted health warning signs in the area. They also contacted regulatory officials with the health department and state Department of Ecology.

The spill occurred in an older portion of the plant, which is now used for wastewater solids storage. The new Vashon Island treatment plant, which King County completed in late 2006, was not affected.

None of the facilities were damaged, and the plant is again operating normally.

People enjoy clean water and a healthy environment because of King County's wastewater treatment program. The county’s Wastewater Treatment Division protects public health and water quality by serving 17 cities, 17 local sewer utilities and more than 1.4 million residents in King, Snohomish and Pierce counties. Formerly called Metro, the regional clean-water agency now operated by King County has been preventing water pollution for more than 40 years.