Which beaches recover first and which to avoid after storms
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. Rain washes bacteria, fertilizers, and other pollutants from land into the ocean through streams, storm drains, and direct runoff. Some beaches recover faster than others depending on drainage, currents, and proximity to runoff sources.
On Big Island, these beaches typically have better water quality sooner after rain: Kohala Coast resort beaches (Hapuna, Mauna Kea, Mauna Lani), Kua Bay, Spencer Beach. These locations are either on dry leeward coasts, far from stream outlets, or have strong ocean currents that flush contamination quickly.
These Big Island beaches are more affected by runoff and take longer to recover: Carlsmith Beach, Richardson Beach, Onekahakaha Beach, Kahaluu Beach (high-risk). Beaches near stream mouths, canals, or in areas that receive heavy rainfall are most impacted.
The Big Island has the most dramatic contrast between windward and leeward. The Kohala Coast is a lava desert receiving less than 10 inches of rain annually — water quality there is almost always excellent. Hilo side beaches receive over 120 inches of rain and have persistent runoff issues. Kona coast beaches are intermediate.
Use the live advisory check on each beach page to see if any DOH advisories are currently posted. If it rained recently and no advisory is posted, that does not necessarily mean the water is clear — not every beach is tested after every storm. Look for brown, murky, or discolored water as a visual indicator. When in doubt, wait.
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Safe to Swim Hawaii provides water quality information based on publicly available DOH data and seasonal patterns. This is not medical or safety advice. Always check current conditions, obey posted signs, and use your own judgment before entering the ocean. Privacy Policy
⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health or any government agency. Water quality ratings are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions.
Always verify current water quality conditions with the Hawaii DOH Clean Water Branch before entering the water.
When in doubt, don't go out. 🤙