Live advisory status for every Big Island beach — Kona vs Hilo, Kohala Coast dryness, Kahaluʻu contamination, and the 72-hour rule
The Big Island’s brown water risk depends almost entirely on which side of the island you are on. Mauna Kea (13,796 ft) and Mauna Loa (13,681 ft) create a massive rain shadow that divides the island into a wet east coast and a dry west coast.
Hilo side (east coast): Receives over 130 inches of rain per year. Multiple rivers — including the Wailuku River, Wailoa River, and numerous smaller streams — discharge into Hilo Bay and along the Hamakua Coast. Brown water advisories are frequent here, especially during winter storms.
Kohala Coast (northwest): The resort corridor from Hapuna Beach to Mauna Lani receives only about 10 inches of rain per year. There are virtually no stream outlets along this stretch. These beaches are among the least affected by brown water in all of Hawaii.
Kona coast (west): Moderately dry at 15–25 inches per year. Kona town and Keauhou see occasional brown water after heavy rain. Kahaluʻu Beach has chronic cesspool contamination that is a year-round problem, not just a rain event issue.
Kahaluʻu Beach in Kona has elevated bacteria levels that are not tied to rain events. The Keauhou area surrounding Kahaluʻu has a high concentration of cesspools that discharge sewage into the groundwater, which then seeps into the nearshore ocean. This creates a chronic contamination problem year-round.
Unlike most brown water situations that improve after 72 hours of dry weather, Kahaluʻu’s contamination is persistent. The DOH has documented consistently elevated bacteria levels at this beach regardless of recent rainfall.
We cannot advise whether any beach is safe. The data shows Kahaluʻu Beach has persistent bacteria contamination from cesspool infrastructure. Check the DOH Clean Water Branch for the latest test results and make your own informed decision.
The Big Island’s massive size and climate divide mean recovery times vary dramatically:
If you are visiting the Big Island and it rains, head to the Kohala Coast. Hapuna Beach and Spencer Beach are typically the least affected by brown water events on the entire island. Always wait the full 72 hours on the Hilo side.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — it is not affiliated with the Hawaii Department of Health or any government agency. Water quality ratings on this site are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions. “No DOH Alerts” means no advisory is currently posted — it does not mean the water was tested and found safe. DOH only monitors a fraction of Hawaii’s beaches, and some areas have no regular testing at all.
Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water. This site is for informational purposes only and should not be the sole basis for any swimming decisions.
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When in doubt, don't go out.