King County ordered to fix power supply problems at sewage plant

KING COUNTY, Wash. — There’s new pressure to fix problems at the West Point Treatment Plant after millions of gallons of partially treated sewage spilled into Puget Sound.

State regulators on Wednesday ordered King County to fix a power supply problem that has plagued the plant for years.

The Washington State Department of Ecology reported that six times, between January 2018 and May 2020, power problems caused more than 4 million gallons of partially treated sewage to be discharged into Puget Sound.

“The consequences of failure at a large plant are high,” said Vince McGowan, Ecology’s Water quality program manager.

King County officials said the quality of the electricity coming into West Point isn’t consistent.

When there’s a power sag for more than three seconds, the pumps shut down, and untreated wastewater goes right into Puget Sound to avoid flooding the plant.

“On average, we get disruptions that come into the plant about once every other month,” said Mark Isaacson, director of King County’s Wastewater Treatment Division.

Isaacson said West Point has a dedicated line from a Seattle City Light substation in Fremont, but because the substation also serves several neighborhoods, it’s vulnerable to disruptions.

“You could have a disturbance 5 miles away,” Isaacson said.

A substation near Seattle Center is the backup, but West Point is at the end of a line it shares with a lot of neighbors.

Seattle City Light stated it is collaborating with King County on solutions and that potential long-term fixes could include a dedicated power supply from a new substation or transmission-level service directly to the plant.

State regulators ordered the county to submit an electrical master plan this year and to take the first corrective actions by the end of 2025.