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TREND REPORT

Hawaii Water Quality — May 11, 2026

Maui water quality is improving (+64pp in 14 days)

By Safe to Swim Hawaii Team · Published May 11, 2026
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BIG ISLAND
Mostly advisory-affected, stable (0% of days with no DOH advisory anywhere)
↑
MAUI
+64pp improving
→
OʻAHU
Mostly advisory-affected, stable (0% of days with no DOH advisory anywhere)
→
KAUAʻI
Mostly advisory-affected, stable (0% of days with no DOH advisory anywhere)

Maui ocean water quality improved 64 percentage points over the last 14 days (36% advisory-free two weeks ago vs. 100% advisory-free now).

If the NOAA 7-day outlook stays dry, the improving trend should continue. See the Maui leaderboard for which individual beaches drove the change.

Where the islands stand today

Big Island

mostly advisory-affected, stable

Big Island has been mostly advisory-affected across both 14-day island-wide advisory-day windows. Our 7 tracked beaches happen not to overlap with the DOH advisories driving this signal — the worsening trend is from island-wide or other-area advisory events. NOAA's 7-day forecast is dry, which should halt new advisory activity and let the existing advisories begin to clear. See the Big Island leaderboard for the beach-by-beach ranking.

Maui

improving

Maui is improving over the last 14 days (+64pp vs. the prior two weeks). 1 of our 6 tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day forecast is dry, so the improving trend should continue. See the Maui leaderboard for the beach-by-beach ranking.

Oʻahu

mostly advisory-affected, stable

Oʻahu has been mostly advisory-affected across both 14-day island-wide advisory-day windows. All 12 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day forecast is mild — scattered showers possible but unlikely to drive new advisories. See the Oʻahu leaderboard for the beach-by-beach ranking.

Kauaʻi

mostly advisory-affected, stable

Kauaʻi has been mostly advisory-affected across both 14-day island-wide advisory-day windows. All 6 of our tracked beaches on the island recorded one or more advisory days in that 30-day history window. NOAA's 7-day forecast is mild — scattered showers possible but unlikely to drive new advisories. See the Kauaʻi leaderboard for the beach-by-beach ranking.

Cleanest beaches today (last 30 days)
Anaehoʻomalu Bay (A-Bay)
30/30 days advisory-free
Clean →
Hapuna Beach
30/30 days advisory-free
Clean →
Honoliʻi Beach
30/30 days advisory-free
Clean →
Most advisory-affected tracked beaches (last 30 days)
Tunnels Beach (Makua)
0/30 days advisory-free
Under advisory →
Lydgate Beach
0/30 days advisory-free
Under advisory →
Kalapaki Beach
0/30 days advisory-free
Under advisory →
NOAA 7-day forecast, per island tourist coast
  • Kohala Coast, Big Island: dry (max 12% chance of rain across next 7 days)
  • South Maui (Wailea / Kihei): dry (max 10% chance of rain across next 7 days)
  • South Shore O’ahu (Honolulu / Waikiki): mild (max 28% chance of rain across next 7 days)
  • Po’ipu, Kaua’i: mild (max 41% chance of rain across next 7 days)

For the always-live per-island outlook, see our Hawaii Water Quality Forecast, which regenerates daily from NOAA + DOH data.

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Live data and deeper context
Hawai’i Water Quality Data Hub — every resource in one place
Hub →
Hawaii Water Quality Forecast — 14-day trend + 7-day NOAA outlook
Live →
Is Hawaii’s Beach Water Getting Cleaner or Dirtier? — YoY DOH data
Trend →
Cleanest Hawaii Beaches Right Now — statewide ranking
Rankings →
Hawaii Citizen Water Testing — 100+ Surfrider BWTF sites
Coverage →
Why Hawaii Water Turns Brown After Rain — stream-mouth data
Data →
Hawaii Sewage Spills Today — live DOH tracker
Live →
Where to Swim During a Brown Water Advisory
Guide →
Brown Water Advisory — live all islands + 72-hour rule
Guide →
Previous report — April 23, 2026
Archive →
Methodology: The island trend uses Hawaii DOH island-wide advisory-day history where available: a day counts as advisory-free only when no DOH advisory was recorded anywhere on that island. If island history is unavailable, the generator labels its tracked-beach-fraction fallback explicitly. The separate beach list summarizes 31 tracked beach histories. Forecast data comes from NOAA National Weather Service (api.weather.gov) at each island’s primary tourist coast. This report is not a swim recommendation; always check the individual beach page and current local conditions before entering the water.