Hawaii health officials are warning residents and visitors to avoid ocean water at beaches on Oahu and Maui after heavy storm runoff triggered islandwide brown-water advisories. The Hawaii Department of Health Clean Water Branch issued advisories for both islands following a series of March storms that caused major flooding and sent polluted runoff into nearshore waters. The advisory does not automatically close every beach, but it signals a heightened public health risk as stormwater can carry sewage, chemicals, animal waste, debris, and disease-causing organisms into the ocean.
The warning comes after severe flooding battered parts of Hawaii, especially Oahu’s North Shore and sections of Maui. The Associated Press reported that officials called it Hawaii’s worst flooding in more than 20 years, with evacuation orders issued for thousands of people on Oahu and flood concerns also rising on Maui. State and local officials are urging people to check current advisories before entering the ocean and to avoid any water that appears brown or murky after rain.
What Hawaii’s Brown Water Advisory Means For Beachgoers
The state’s general health advisory guidance says runoff from heavy rain can carry contaminants from overflowing cesspools and septic systems, storm drains, farms, roadways, and other polluted sources into streams and coastal water. Health officials say people should avoid swimming, surfing, wading, or drinking water from freshwater streams and ponds after major rain events. The City and County of Honolulu told Oahu residents to stay out of ocean waters for at least 72 hours after the last rainfall and continue avoiding any area where the water still looks brown or murky.
The city also warned that runoff can bring floating debris and other hazards that are not always visible from shore. Officials stressed that there were no blanket beach closures tied to the advisory, but they urged the public to make informed decisions and prioritize safety while the warning remained in effect. Extra caution is recommended near stream mouths, drainage outlets, and places where runoff empties into the ocean.
Testing And Storm Recovery Data Support The Public Health Warning
State officials noted that follow-up environmental monitoring reinforced the need for caution as recovery continued. In an April 2 news release from Gov. Josh Green’s office, the Hawaii Department of Health said it collected samples from beach sites on Oahu’s North Shore and found that several locations exceeded the state’s beach action value for enterococci, a bacteria indicator used to assess possible fecal contamination and swimmer illness risk.
The same release said flood-related mud, sediment, and nearshore samples from impacted areas detected pathogens, including E. coli, Enterococcus, and Salmonella in some locations. Officials cautioned that testing captures only a point in time and said people should still avoid waters that appear brown or murky, especially after storms or heavy rain. The advisory remained in place for communities on Maui and Oahu as the state continued posting updates through its Clean Water Branch advisory system and storm recovery information page.
