Kona storm triggers wastewater overflow at Lahaina reclamation facility

Approximately 200,000 gallons of partially treated wastewater overflowed from the Lahaina Wastewater Reclamation Facility on March 21 during Kona Storm 2, according to the County of Maui Department of Environmental Management.

The incident occurred when heavy rainfall caused excessive stormwater infiltration into the sewer system, surcharging a manhole and triggering the overflow between approximately 2 p.m. and 11 p.m. The discharge consisted primarily of filter backwash water and treated wastewater that had not been fully disinfected.

Officials said the overflow entered a storm drain system already carrying significant storm flows, making it likely that the combined discharge reached the ocean. Warning signs have been posted in the affected area, and the Hawaiʻi State Department of Health has been notified.

The event highlights ongoing challenges utilities face with wet weather overflows, particularly in systems vulnerable to inflow and infiltration during extreme storm events.