Cleanest Hawaii Beaches Right Now

DOH only tests ~47 stations across the four main islands. Surfrider Foundation's volunteer Blue Water Task Force tests 100+ additional sites that DOH doesn't routinely visit. Below are the worst recent BWTF readings within Hawaii's coverage:

How This Ranking Is Calculated

Every Hawaii Department of Health advisory is a public record — Beach Advisories are issued when bacteria levels at a monitoring station exceed the EPA recreational threshold of 130 CFU/100 mL enterococcus, and Brown Water Advisories are issued when storm runoff makes coastal water visibly turbid.

We count the number of days each beach has been under any DOH advisory in the last 30 days. Fewer days under advisory means a higher rank. When a DOH advisory is island-wide (“Brown Water Advisory, Island of Hawaii”), every monitored beach on that island is counted as under advisory for those days. When an advisory is station-specific, only the matching beach is counted.

The ranking measures water quality exposure only — days under advisory. It is not a swim-safety rating. A beach can rank high here but still have strong currents, shore break, rip currents, or no lifeguards. Always check the individual beach page for physical-hazard information and live DOH status before you swim.

Why the Big Island's Kohala Coast is always at the top

The top-ranked beach this month (and in most months) is Hapuna Beach on the Big Island's Kohala Coast. That is not a coincidence. Three geographic factors drive the ranking:

• Rainfall. The Kohala Coast receives under 10 inches of rain per year — one of the driest coastal climates in the U.S. Less rain means less runoff means fewer Brown Water Advisories.
• Watershed geography. No significant streams reach the Kohala resort beaches. Beaches at stream mouths (Hanalei Bay, Kailua, Haleiwa) catch every runoff event from a wide watershed.
• Wastewater infrastructure. Kohala Coast resorts use modern wastewater systems, not the ~88,000 cesspools that line older Hawaii coastlines. Cesspool leakage is a year-round bacteria source even in dry weather.

South Maui (Wailea, Makena, Kihei) benefits from the same three factors on a slightly wetter coast and consistently ranks second. North Shore O'ahu (Haleiwa, Sunset) and Kaua'i's north shore (Hanalei) are at the opposite end — wet, stream-fed, and advisoried for most of the typical month.

Data Sources

This ranking is built from:

• Hawaii DOH Clean Water Branch public API — Beach Advisory and Brown Water Advisory events, including bacteria Count values when an advisory is issued.
• DOH station registry — the official list of monitoring stations, mapped to each beach page.
• EPA Recreational Water Quality Criteria — the 130 CFU/100 mL enterococcus threshold referenced throughout.

Every beach in this ranking has its own page with the 30-day daily-bar chart showing exactly which days were under which kind of advisory, plus live DOH status. Click the beach name to see its full history.

Which Hawaii beach has the cleanest water right now?

Based on the last 30 days of Hawaii Department of Health advisory data, Anaehoomalu Bay (A-Bay) is currently the top-ranked beach by days advisory-free, with 30/30 days clean. The Big Island's kohala coast typically has Hawaii's driest coastal climate and the lowest historical advisory frequency because there is minimal rainfall, no major streams, and modern wastewater infrastructure.

Does ’cleanest’ mean safe to swim?

No. This ranking measures water quality (bacteria levels and advisory frequency) only. A beach can rank high for clean water but still have physical hazards like strong currents, shore break, rip currents, or no lifeguards. Always check current DOH advisories and local surf/current conditions before entering the water. This page is for comparing beaches on water quality alone.

Why are some Hawaii beaches almost always under advisory?

Three factors drive consistent advisory status: (1) Rainfall and runoff — wet windward and north-shore coasts get hit by rainfall far more often than dry leeward coasts. (2) Watersheds and streams — beaches near stream mouths receive runoff carrying sediment, bacteria from cesspools, and urban pollutants. (3) Brown Water Advisory scope — DOH often issues island-wide advisories that apply to every monitored beach on the island, inflating the under-advisory day count even at sheltered locations.

How often is this ranking updated?

The ranking refreshes daily from the Hawaii Department of Health Clean Water Branch public API. The 30-day window is a rolling window that ends at the current date, so tomorrow's ranking will drop today's oldest day and add tomorrow as the newest. Last updated: 2026-05-20.