Kauai Wastewater Plant Spilling 70,000 Gallons Daily Since Monday

The Līhuʻe Wastewater Treatment Plant has been releasing approximately 70,000 gallons of wastewater per day since about 10 a.m. on March 17, with the county's Wastewater Management Division issuing public updates on March 18, 19, and 20 as the intermittent spill continued through the week.

County officials said the discharge has remained confined within the facility and has not reached public areas or state waters. The spills are not random: they occur during peak flow periods, specifically early morning, late morning, and evening hours, and officials warned that additional discharges could continue during heavy rainfall.

The overflow originated from the plant's effluent tank after wastewater had already passed through biological treatment and UV disinfection, officials said. Though the county described the site as fully contained, some overflow may have entered nearby drainage ditches that do not connect to state waters.

The Wastewater Management Division traced the problem to decreasing capacity in the plant's underground injection control wells, which cannot absorb the volumes produced when storm-driven infiltration and inflow push flows higher. Crews have been applying additional disinfection measures in affected areas while monitoring flows to prevent any off-site spread.

The Līhuʻe plant's troubles were not isolated. The county also reported a separate spill at the Waimea Wastewater Treatment Plant totaling about 285,750 gallons between 8 p.m. Friday and 6 a.m. Saturday. That spill was also confined on-site, though some overflow may have entered adjacent drainage ditches. On Saturday, the county reported yet another spill, between 10:30 a.m. and 2:30 p.m., that released about 64,000 gallons. The same storm system triggered multiple overflows on Oahu as well.

The Wastewater Management Division said it is working on both short-term and long-term projects to address the injection well capacity problem, including evaluating options to expand UIC well capacity and increase distribution of R-1 recycled water to handle higher storm flows. The division is coordinating with the Hawaiʻi Department of Health's Clean Water Branch on immediate and lasting solutions.

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