Step-by-step: what the advisory says, what it actually means, and what to do.
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. Advisories are posted by the Hawaii DOH Clean Water Branch. They are informational only and do not close beaches. Understanding what they mean is critical for making informed decisions.
Brown Water Advisory: Issued for wide areas after rain. Based on VISUAL observation, not lab testing. Covers entire coastlines or island sections.
Beach Advisory: Issued for a SPECIFIC beach based on LAB RESULTS showing Enterococcus > 130 CFU/100mL.
Statewide Advisory: Rare. Issued during major storm events. All island coasts affected.
A brown water advisory for "South Shore Oʻahu" does not mean every beach on the south shore has brown water. It means the DOH has observed brown water somewhere on the south shore. Your specific beach may be clear, especially if it is on a dry section of coast away from stream mouths. Check the specific locations listed in the advisory and compare with your beachʻs geography.
This is the most misunderstood part. "Informational only" means the advisory carries NO legal weight. The beach is still open. Lifeguards are still on duty. There are no barriers or signs prohibiting entry. The DOH is simply informing you that water quality may be compromised. The decision to swim is entirely yours — but the data strongly suggests caution.
Hours 0-24: Peak contamination. Bacteria levels can be 10-100x above safe thresholds. Water is visibly brown near stream mouths.
Hours 24-48: Open-coast beaches begin clearing. Enclosed bays and river-adjacent beaches remain elevated.
Hours 48-72: Most beaches returning to near-normal visually. Bacteria declining but may still be elevated.
Hour 72+: Most open-coast beaches at baseline. Continue monitoring enclosed bays.
You now have the data. The advisory type tells you how it was determined. The location tells you if it is relevant. The timeline tells you where you are in the recovery. Your individual risk tolerance, health status (immunocompromised people face higher risk), and the specific beachʻs geography all factor in. When in doubt, donʻt go out.
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⚠️ 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. 🤙