Water quality status and bacteria risk rating
📍 In Honolulu between Waikiki and downtown, next to the Ala Moana Shopping Center
Ala Moana Beach Park is Hawaii's busiest beach, drawing an estimated 4 million visitors per year. It is a DOH Tier 1 beach, meaning it gets tested at least weekly due to high use and multiple risk factors. The beach has a documented history of bacteria exceedances, including a reading of 1,013 enterococci per 100mL in January 2018 — nearly 8 times the safe swimming limit of 130.
Several factors converge here: the Ala Wai Canal outlet nearby discharges urban runoff from Honolulu's watersheds, storm drains along the park carry street-level pollutants, and a breakwater limits water circulation in the swimming area. DOH notes that the sheer number of bathers itself increases bacteria risk.
Based on: DOH Tier 1 beach, advisory history (Jan 2018, Oct 2018, Sep 2019, Feb 2025), Hawaii Business Magazine reporting on DOH beach monitoring
The 72-hour rule is especially important at Ala Moana. After heavy rain, the Ala Wai Canal flushes contaminated runoff from Honolulu's central valleys directly into the ocean near this beach. Storm drains throughout the park also carry pollutants. Even if the water looks clear, bacteria can remain elevated for days. Stay out of the water if the Ala Wai looks brown or turbid where it meets the harbor near Magic Island.
The Ala Wai Canal is one of Hawaii's most polluted waterways. Built in 1928 to drain the wetlands that became Waikiki, it now channels runoff from the Manoa, Palolo, and Makiki valleys through central Honolulu and out into the ocean near the Ala Wai Boat Harbor — right next to Magic Island at the Diamond Head end of Ala Moana Beach Park.
Researchers at the University of Hawaii have documented toxic levels of Vibrio vulnificus (a flesh-eating bacterium) in the canal. In 2006, a major sewage line break forced the city to dump 48 million gallons of untreated sewage into the canal, closing nearby beaches for a week. Over 11,000 cesspools on O'ahu, many in the Ala Wai watershed, continue to leach human waste into groundwater and eventually the canal.
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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. This site is for informational purposes only and should not be the sole basis for any swimming decisions.
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When in doubt, don't go out. 🤙