Hawaii Water Quality Today

Safe to Swim Hawaii pulls data from six sources to give you the most complete picture of ocean conditions:

• Hawaii DOH Clean Water Branch — Official advisories for brown water, sewage spills, and bacteria. Updated as the DOH posts them.
• USGS Stream Monitoring — Real-time discharge and turbidity from 25 stream gauges near major beaches. High stream flow = more runoff reaching the ocean.
• NOAA CO-OPS — Tide levels and ocean temperature from 5 stations across the islands.
• NDBC Wave Buoys — Wave height and period from 5 offshore buoys. High surf stirs up sediment and makes conditions more dangerous.
• NWS Honolulu — Flood watches, high surf warnings, and marine advisories that affect ocean safety.
• City & County of Honolulu ENV — Kailua Bay bacteria monitoring at 7 stations plus wastewater spill reports.

No other Hawaii beach site combines all six data sources in one place. The DOH website shows only their own advisories — it does not include stream conditions, ocean data, weather alerts, or city-level monitoring.

Hawaii has a water quality infrastructure problem that most visitors never hear about:

The DOH tests 57 of over 300 swimmable beaches — that leaves most beaches with no regular monitoring at all. After heavy rain, the DOH pauses routine testing during brown water advisories, creating an information gap during the exact conditions when bacteria is most likely elevated.

Cesspools — essentially holes in the ground where household wastewater is dumped without treatment — are the single largest source of nearshore contamination. The sewage seeps through porous volcanic rock into groundwater and coastal waters. UH Hilo dye tests have confirmed cesspool wastewater reaching the shoreline at beaches like Kahaluʻu Beach Park in Kona. Read our full investigation into Hawaii’s 88,000 cesspools →

This is why water quality varies so dramatically between beaches just a few miles apart. A beach with no streams, no cesspools, and good ocean circulation (like Hapuna Beach) will have virtually zero bacteria risk. A beach at a stream mouth in a cesspool-heavy area (like Kalapaki Beach) can fail every single bacteria test.

On Oahu, the most-watched example is the Ala Wai Canal's discharge into Waikiki after heavy rain — see our Waikiki brown water advisory today page for zone-by-zone recovery times (west end hit first, Diamond Head end recovers soonest).

Want to see the full ranking? We publish a daily leaderboard of Hawaii's cleanest beaches right now, sorted by days advisory-free in the last 30 days using the DOH Clean Water Branch data directly.