Equipment failures caused between $49 million and $57 million of damage to the West Point Wastewater Treatment Plant, according to an analysis released Friday.
The repair costs are expected to be covered by property insurance and will not impact King County sewer rate in 2017-18, according to the King County Wastewater Treatment Division. King County will be responsible for a $250,000 deductible.
Insurance is not expected to cover potential regulatory fines or additional environmental monitoring.
CH2M engineers calculated the repair cost to include existing orders for broken equipment, work orders, staff labor changes, and asset inventories. It also accounts for unknown costs, such as building code changes and highly specialized equipment.
King County’s property insurance covers costs up to $500 million, with a flood-related damage sub-limit of $250 million.
The West Point Treatment Plant in Discovery Park suffered a historic breach February 9 when an equipment failure caused untreated wastewater and stormwater to flow into the Puget Sound.
An initial forensics report determined devices that were likely bent through normal maintenance procedures caused the mechanical failure. Switch floats were supposed to rise as the water rose, but they had bent rods, preventing them from rising and signaling the alarm.
All critical systems were repaired by April 27, and the treatment plant received compliance with environmental permits May 11.
The King County Council has also approved an investigation of the incident.