Water quality status and bacteria risk rating
📍 Kaʻu coast, about 1 hour south of Kona, between Volcano and South Point
Punaluʻu Black Sand Beach has generally good water quality with some factors to watch. The beach is remote with no nearby development, and open ocean exposure provides decent water circulation. However, freshwater springs seep through the volcanic rock along the shoreline, mixing cold freshwater with the ocean. This groundwater seepage can potentially carry trace contaminants.
This is primarily a sightseeing and turtle-watching beach rather than a swimming destination. Hawaiian green sea turtles (honu) frequently rest on the black sand — you must stay at least 15 feet away by law. The rocky entry and open ocean conditions make swimming challenging. DOH monitoring is limited at this remote location.
Based on: Remote location, freshwater spring influence, open ocean exposure, limited DOH monitoring
Even at relatively low-risk beaches like Punaluʻu, the Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. Punaluʻu has no stream discharge, but the freshwater springs that feed the beach can carry increased groundwater contaminants after heavy rainfall. The Kaʻu coast receives moderate rainfall — check conditions before visiting.
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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. 🤙