HONOLULU — The City and County of Honolulu’s Department of Environmental Services (ENV) is responding to wastewater spills at facilities in ʻĀhuimanu, Kailua and Waimanalo caused by heavy rain and system inflow and infiltration on Friday, March 20, 2026.
- ʻĀhuimanu Preliminary Treatment Facility: At 9:20 a.m., elevated flows exceeded storage capacity, causing a manhole at the facility to overflow into an on-site storm runoff retention basin. The basin subsequently reached capacity and discharged into ʻĀhuimanu Stream. The spill is ongoing.
- Kailua Regional Wastewater Treatment Plant: At 10:10 p.m., the Tunnel Influent Pump Station (TIPS) reached maximum capacity. Personnel installed portable pumps to manage the inflow. During testing and startup, approximately 30,000 gallons of wastewater were discharged onto an adjacent grassy area, flowing into Nuʻupia Pond. The spill was stopped at 10:20 p.m.
- Waimanalo Wastewater Treatment Plant: At 10:00 p.m., high flows overwhelmed the facility, causing an ongoing spill at the Headworks and an initial spill at the Final Clarifier scum pit that reached Puha Stream. While the scum pit spill was stopped at 1:00 a.m. on March 21, the Headworks spill remains active.
ENV crews are actively monitoring conditions and calculating total discharge volumes for all locations.
Following the cessation of severe weather, ENV will post warning signs and initiate water quality sampling. Residents are advised to stay out of the affected waterways until signs are removed.
Department of Environmental Services
City and County of Honolulu
YouTube: @CCHNL_ENV
Instagram: @hnl.env
Facebook: HNL.ENV1
