Honolulu, Hawaii Tap Water Quality Report
Serving utility: Honolulu-Windward-Pearl Harbor
Updated March 2026 • Data from EWG Tap Water Database & EPA SDWIS
High Priority Concerns
Honolulu tap water has 11 contaminants exceeding EWG health guidelines, including Chromium (hexavalent), Perfluorohexane sulfonate (PFHXS), Total trihalomethanes (TTHMs). Additionally, 10 known or suspected carcinogens were detected, including Chromium (hexavalent), Total trihalomethanes (TTHMs), Haloacetic acids (HAA9).
Water Provider Information
Contaminants Detected
| Contaminant | Detected Level | EWG Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Chromium (hexavalent) carcinogen | 1.78 ppb | 0.02 ppb | No legal limit | Above guideline |
| Perfluorohexane sulfonate (PFHXS) | 0.03 ppt | 0.00 ppt | 10 ppt | Above guideline |
| Total trihalomethanes (TTHMs) carcinogen | 3.76 ppb | 0.15 ppb | 80 ppb | Above guideline |
| Haloacetic acids (HAA9) carcinogen | 0.92 ppb | 0.06 ppb | No legal limit | Above guideline |
| Dibromoacetic acid | 0.42 ppb | 0.03 ppb | No legal limit | Above guideline |
| Bromochloroacetic acid | 0.14 ppb | 0.02 ppb | No legal limit | Above guideline |
| 1,2,3-Trichloropropane | 0.00 ppb | 0.00 ppb | No legal limit | Above guideline |
| Bromoform carcinogen | 2.77 ppb | 0.50 ppb | No legal limit | Above guideline |
| Nitrate and nitrite carcinogen | 0.41 ppm | 0.14 ppm | 10 ppm | Above guideline |
| Nitrate carcinogen | 0.41 ppm | 0.14 ppm | 10 ppm | Above guideline |
| Haloacetic acids (HAA5) carcinogen | 0.24 ppb | 0.10 ppb | 60 ppb | Above guideline |
| 1-Butanol | 0.38 ppb | N/A | No legal limit | Below guideline |
| Barium | 5.02 ppb | 700 ppb | 2,000 ppb | Below guideline |
| Chlorate | 29.10 ppb | 210 ppb | No legal limit | Below guideline |
| Chlordane | 0.01 ppb | 0.03 ppb | 2 ppb | Below guideline |
| Chromium (total) | 1.63 ppb | N/A | 100 ppb | Below guideline |
| Dibromochloromethane carcinogen | 0.07 ppb | 0.10 ppb | No legal limit | Below guideline |
| Dichloroacetic acid carcinogen | 0.10 ppb | 0.20 ppb | No legal limit | Below guideline |
| Dieldrin | 0.01 ppb | N/A | No legal limit | Below guideline |
| Fluoride | 0.01 ppm | N/A | 4 ppm | Below guideline |
| Heptachlor epoxide | 0.00 ppb | 0.01 ppb | 0.20 ppb | Below guideline |
| Manganese | 0.11 ppb | 100 ppb | No legal limit | Below guideline |
| Radium, combined (-226 and -228) | 0.03 pCi/L | 0.05 pCi/L | 5 pCi/L | Below guideline |
| Strontium | 0.11 ppb | 1,500 ppb | No legal limit | Below guideline |
| Trichloroacetic acid carcinogen | 0.07 ppb | 0.10 ppb | No legal limit | Below guideline |
| Vanadium | 11.30 ppb | 21 ppb | No legal limit | Below guideline |
Health Context
Chromium (hexavalent) carcinogen
Exposure to elevated levels of this contaminant may pose health risks. See EWG and EPA guidelines for more information.
Perfluorohexane sulfonate (PFHXS)
Exposure to elevated levels of this contaminant may pose health risks. See EWG and EPA guidelines for more information.
Total trihalomethanes (TTHMs) carcinogen
Exposure to elevated levels of this contaminant may pose health risks. See EWG and EPA guidelines for more information.
Haloacetic acids (HAA9) carcinogen
Exposure to elevated levels of this contaminant may pose health risks. See EWG and EPA guidelines for more information.
Dibromoacetic acid
Exposure to elevated levels of this contaminant may pose health risks. See EWG and EPA guidelines for more information.
Recommended Filtration for This Water
Echo RO System
Reverse osmosis filtration removes up to 99.9% of contaminants including heavy metals, PFAS, disinfection byproducts, and more. The gold standard for drinking water purification.
View RO SystemsEcho Under-Sink Filter
Point-of-use filtration designed to remove heavy metals, lead, arsenic, and PFAS right at your kitchen faucet.
View Under-Sink FiltersEcho Hydrogen Water Flask
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Shop Hydrogen FlaskFrequently Asked Questions
Is Honolulu tap water safe to drink?
Honolulu tap water meets EPA legal standards for drinking water. However, 11 contaminants exceed stricter EWG health guidelines, and 10 known carcinogens were detected. While legally compliant, additional filtration is recommended for optimal safety.
What contaminants are in Honolulu water?
A total of 26 contaminants were detected in Honolulu tap water, including Chromium (hexavalent), Perfluorohexane sulfonate (PFHXS). Of these, 11 exceed EWG health guidelines.
What's the best water filter for Honolulu?
For Honolulu tap water, we recommend a reverse osmosis (RO) system for drinking water — it removes up to 99.9% of contaminants including heavy metals, PFAS, and disinfection byproducts. For shower and bath water, a whole-home filtration system reduces chlorine and volatile organics.
Where does Honolulu get its water?
Honolulu tap water is provided by Honolulu-Windward-Pearl Harbor, serving approximately 631,389 people. For detailed source water information, contact your local utility or visit the EPA's SDWIS database.
Nearby City Water Reports
Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)
Last updated: March 2026
Methodology: Contaminant levels are compared against both EPA legal limits (Maximum Contaminant Levels) and EWG health guidelines, which are often stricter and based on the latest scientific research.
