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Water Quality Rankings

Hawaii’s Worst Beaches for Bacteria

Ranked by bacteria test failure rates from Hawaii DOH monitoring and Surfrider Foundation testing data.

How We Ranked These Beaches

These rankings are based on enterococcus bacteria testing data from the Hawaii Department of Health’s Clean Water Branch (weekly Tier 1 monitoring) and the Surfrider Foundation’s 2024 Blue Water Task Force results. A “failure” means the water sample exceeded the EPA’s Beach Action Value of 130 enterococci per 100 mL — the threshold above which illness risk increases significantly.

80%
Of tested Hawaii beaches exceeded limits at least once (Surfrider 2024)
57
Of 250+ beaches tested weekly by DOH
130
EPA limit: enterococci per 100 mL
The Worst Offenders
#1
Kalapaki Beach· Kaua’i (Lihue)
100% bacteria failure rate since 2016
Every single water sample collected at Kalapaki since 2016 has exceeded the safe bacteria threshold. Located near the mouth of the Nawiliwili Stream in Lihue, this beach receives chronic runoff from the surrounding watershed. Despite being steps from the Kaua’i Marriott, the DOH has maintained a persistent advisory. Full Kalapaki Beach guide →
#2
Kahalu’u (Kaneohe Bay)· O’ahu
92% bacteria failure rate
Not to be confused with the Big Island’s Kahalu’u Beach Park in Kona, this O’ahu location in the Kaneohe Bay area is one of the most contaminated coastal areas in the United States. The surrounding watershed has a high density of cesspools feeding directly into the bay. No dedicated page yet — check the main site for Kaneohe Bay data.
#3
Hanalei Bay· Kaua’i (North Shore)
DOH-impaired for enterococcus since 2004
Hanalei Bay has been officially listed as impaired by the DOH for over 20 years. Four streams discharge into the bay, and over 360 active cesspools line the watershed from Hanalei to Ha’ena. Stanford/USGS studies confirmed human wastewater markers. Surfrider 2024 data shows “The Bowl” polluted roughly 20% of the time. Risk varies by location — the river mouth area (Black Pot/Pier) is worst. Full Hanalei Bay guide →
#4
Hanakaoo Beach Park· Maui (West Maui)
1,298/100mL in Feb 2026 (10x the safe limit)
Also known as “Canoe Beach,” Hanakaoo sits between Ka’anapali and Lahaina and has shown a worsening trend: 178/100mL in 2018, 238 in 2019, 137 in 2020, and now 1,298 in February 2026. Separate issue from the Lahaina injection wells (those affect Kahekili Beach Park, 1.5 miles north). Full Hanakaoo Beach guide →
#5
Ala Moana Beach Park· O’ahu (Honolulu)
1,013/100mL in Jan 2018 (8x limit) — recurring pattern
One of the most visited beaches in Hawaii (~4M visitors/year) but sits adjacent to the Ala Wai Canal, which has documented Vibrio vulnificus (flesh-eating bacteria). A breakwater limits water circulation. In 2006, 48 million gallons of raw sewage were dumped into the Ala Wai, closing nearby Waikiki Beach for a week. Multiple exceedances recorded: 2018, 2019, and 2025. Full Ala Moana guide →
#6
Kahalu’u Beach Park· Big Island (Kona)
2,005/100mL in Jan 2026 (15x limit)
The Big Island’s most popular snorkeling spot (~400K visitors/year). A UH Hilo dye tracer study confirmed that cesspool wastewater from nearby homes reaches the shoreline. The ancient rock wall breakwater that makes snorkeling easy also limits water circulation, meaning contaminants persist longer. Recurring spikes: 2019 (324), 2023 (306), 2025 (164), 2026 (2,005). Full Kahalu’u Beach guide →
#7
Spencer Beach Park· Big Island (Kohala Coast)
178/100mL in Feb 2026
A popular family beach on the Kohala Coast that exceeded the 130/100mL threshold in February 2026. While not a chronic offender like the beaches above, its location near a stream mouth means it’s vulnerable to elevated bacteria after rain events.
On the Other End — Hawaii’s Cleanest Beaches

Consistently Clean Water

These beaches consistently test well below bacteria thresholds. They share common traits: open-ocean exposure, no stream mouths, dry leeward coasts, and minimal cesspool density in the surrounding watershed.

Hapuna Beach · Big Island — Kohala Coast, pristine
Low
Makena / Big Beach · Maui — No development, no streams
Low
Hanauma Bay · O’ahu — Protected marine reserve
Low
Poipu Beach · Kaua’i — Dry south shore, tests clean
Low
Wailea Beach · Maui — Cleanest coast on Maui
Low
Why Hawaii Has a Bacteria Problem

83,000 Cesspools

Hawaii has more cesspools per capita than any other US state. These underground pits collect household sewage and let it leach directly into the ground — and eventually into the ocean. The state’s Act 125 (2017) requires all cesspools to be upgraded by 2050, but progress has been slow and the cost is estimated at $1.75 billion.

The problem is worst on Kaua’i (especially the North Shore), the Big Island (especially Hilo and older Kona neighborhoods), and rural O’ahu. Areas served by modern sewer systems — like resort-heavy South Maui and the Kohala Coast — generally have much better water quality.

The Surfrider Foundation’s 2024 data showed that 80% of tested Hawaii beaches exceeded EPA health limits at least once during the testing period. Meanwhile, EPA BEACH Act funding — which supports the DOH’s beach monitoring program — was potentially targeted for elimination in the FY2026 federal budget.

Check all Hawaii beaches & hotels →

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⚠️ Important Disclaimer

Safe to Swim Hawaii is an independent passion project — it is not affiliated with the Hawaii Department of Health or any government agency. Water quality ratings on this site are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions. “No DOH Alerts” means no advisory is currently posted — it does not mean the water was tested and found safe. DOH only monitors a fraction of Hawaii’s beaches, and some areas have no regular testing at all.

Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water.

When in doubt, don’t go out. 🤙

© 2026 Safe to Swim Hawaii · Independent passion project · safetoswimhawaii@gmail.com