Maui's most dramatic coastline — water quality & visitor guide
📍 North Maui Coast — Narrow road access, living Hawaiian community
Kahakuloa Bay has excellent water quality for a north Maui location. The small village has minimal wastewater impact, the bay receives good ocean circulation, and the remote setting keeps pollution sources low. The DOH does not monitor this area regularly. The main concern is runoff from the steep surrounding valleys during heavy rainfall, which can temporarily cloud the water.
Most visitors come to Kahakuloa for the dramatic scenery — the towering Kahakuloa Head, the lush valley, and the historic village — rather than for swimming. The beach itself is a small black pebble beach that can be rough in winter.
The steep valleys around Kahakuloa funnel significant runoff into the bay after rain. Wait 48–72 hours after heavy rain before swimming. Also note the narrow road becomes more dangerous when wet.
Top-rated experiences near this beach. Check water quality above, then plan your trip.
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Free Maui water quality alerts for North Shore and West Maui beaches.
Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii DOH.
Verify with the Hawaii DOH Clean Water Branch before entering.
This site does not recommend or advise anyone to swim at any beach. We share government data and geographic analysis so you can make your own informed decisions. By using this site you accept full responsibility for your own safety. See our Terms of Use for full details.
When in doubt, don't go out. 🤙
Hawaii’s Department of Health monitors approximately 57 beaches statewide through regular bacteria testing. However, with over 300 swimmable beaches across the islands, many popular spots have no regular testing program. Water quality varies significantly based on rainfall, stream proximity, coastal development, and ocean circulation patterns.
After heavy rain, streams and storm drains carry bacteria, sewage, pesticides, and sediment into coastal waters. The DOH recommends staying out of the ocean for at least 48 to 72 hours after heavy rain, even if the water appears clear. Brown or murky water is a visible sign of contamination, but bacteria can be present in clear water near stream mouths.
This site aggregates data from six sources — DOH advisories, USGS stream monitoring (25 stations), NOAA tide and temperature data, NDBC wave buoys, NWS weather alerts, and City & County of Honolulu water testing — to provide a more complete picture than any single source.
The 72-hour rule is the standard guideline from the Hawaii Department of Health: avoid swimming for at least 72 hours after heavy rain stops, especially near stream mouths, canal outlets, and areas with brown or discolored water. This applies to all beaches across all islands.
Bacteria from urban runoff, agricultural land, and aging cesspool systems enters the ocean through streams and storm drains. Hawaii has approximately 88,000 cesspools — more than any other state — many of which leak untreated sewage into groundwater that eventually reaches the coast. Beaches near known cesspool contamination areas carry higher risk, particularly after rainfall.
⚠️ 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.
This site does not recommend or advise anyone to swim at any beach. We share government data and geographic analysis so you can make your own informed decisions. By using this site you accept full responsibility for your own safety. See our Terms of Use for full details.
When in doubt, don’t go out. 🤙