20,000-gallon wastewater spill at Waimea Wastewater Treatment Plant on Kauaʻi

The public is advised of an estimated 20,000-gallon wastewater spill that occurred between approximately 9:00 a.m. and 10:20 a.m. on Sept. 8, 2026, in the Waimea Wastewater Treatment Plant (WWTP).

The spill was limited to an overflow from the Disk Filter following biological treatment at the Waimea WWTP. The overflow subsequently entered the adjacent drainage ditch.

The spill resulted from power outages and rainfall associated with Hurricane Lowell, which impacted the Waimea area. The power outages caused electrical failures at the plant, while increased rainfall led to elevated infiltration and inflow within the collection system. These conditions generated a surge in flows that exceeded the capacity of the disk filter, ultimately resulting in the spill

Operators promptly responded to restore the equipment to operational status. County crews promptly disinfected the affected area, and thoroughly cleaned the area.

Anyone with questions may contact Donald Fujimoto with the Wastewater Management Division at 808-241-4083 or email dfujimoto@kauai.gov.