Kauai officials advise no swimming at Hanalei Bay after runoff

Kauai Ocean Safety Bureau officials advised no swimming or other ocean activities at Hanalei Bay on July 9 after heavy runoff turned the water brown. County warning signs were already posted, and ocean safety staff were monitoring the bay.

Brown water is not just cloudy water. Hawaii Department of Health guidance defines brown water as stormwater runoff that can carry harmful microorganisms and pollutants, and it can also pick up pathogens from cesspools in unsewered areas. On Kauai’s North Shore, that means the water can look calm from the beach while still posing a health risk for swimmers, boogie boarders, and keiki playing near the shoreline.

The county instructed people to stay out of Hanalei Bay until conditions improve and to check current ocean conditions before heading out. Updates are available from any county lifeguard station, the county’s Safe Beach Day site, or the Ocean Safety Bureau at 808-241-4984.

Hawaii Department of Health guidance advises staying out of brown water for at least 48 to 72 hours after rain stops, but runoff can linger longer if rain keeps falling or if streams keep pushing sediment and contamination into the bay.

The July 9 alert followed a pattern of runoff-related warnings on Kauai’s North Shore this year. County officials issued a north-facing-shores advisory on May 11 because of heavy runoff and brown water, and another on Jan. 12 because of hazardous ocean conditions. County also posted a Hanalei Bay brown-water advisory on Jan. 27, 2025.

A separate state advisory for Waioli Beach on July 7 covered the middle of the bay before the county warning went up. Hawaii’s BEACH program issues those notices.