Is it safe to swim today? Check live DOH advisory status — bacteria risk rating, 72-hour rain rule, and Kawainui Marsh drainage
📍 On Oʻahu's windward coast, about 30 minutes over the Pali from Waikiki
Is Kailua Beach safe to swim today? In dry weather: yes — Kailua carries a moderate 2/5 bacteria risk and passes DOH testing most of the time. After rain: wait at least 72 hours. Kawainui Marsh — Hawaii's largest wetland — and Makawao Stream drain directly onto the south end, spiking bacteria after storms. If the water looks brown, stay out regardless of what any advisory says. Avoid the south end near the stream outlets until water clears and 72 hours have passed since rain stopped. Check live advisory status above.
Kailua Beach is a DOH Tier 1 monitored beach that generally passes bacteria testing under normal conditions. However, it sits at the outlet of the Kawainui Marsh system — the largest wetland in Hawaii — which drains through Kaelepulu Stream and Kawainui Canal into Kailua Bay.
After heavy rain, these waterways carry urban runoff, sediment, and potentially elevated bacteria into the nearshore waters. The stream outlets are on the south end of Kailua Beach near the boat ramp. The northern end of the beach (toward Lanikai) tends to be less affected because it is farther from the drainage outlets.
Based on: DOH Tier 1 beach monitoring, Kawainui Marsh drainage proximity, geographic risk assessment
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain, even if the water looks clear. At Kailua Beach, this is important because the Kawainui Marsh system drains a large watershed into Kailua Bay. After storms, the south end of the beach near the stream outlets will be more affected than the north end toward Lanikai.
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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. 🤙