Is Downtown Honolulu, HI Tap Water Safe to Drink?
Graded A+ with no contaminants above EPA limits. Here's everything we tested and how Downtown Honolulu ranks. What to do next ↓
99.3/100
waterverge.com Downtown Honolulu, HI — Water Quality Report
Downtown Honolulu's drinking water received a grade of A+ (99.3 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 3,440 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. PFAS testing under UCMR 5 found no detectable forever chemicals.
The system has 9 violations on record, including 3 health-based violations. All violations have been resolved.
What to know about Downtown Honolulu's water
Downtown Honolulu ranks #4 out of 66 cities in Hawaii for water quality, placing it one of the best in the state.
Downtown Honolulu relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
Water quality score
See methodology →Is Downtown Honolulu, HI water safe to drink?
Based on EPA testing data, Downtown Honolulu's tap water is generally safe to drink. The water system earned a grade of A+ (99.3/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 3,440 residents using groundwater (wells).
Recent water quality updates for Downtown Honolulu
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Downtown Honolulu's water quality assessment. Grade: A+ (99.3/100).
Federal disaster declaration (FEMA DR-3529). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3404). Hurricane event — may have impacted local water infrastructure.
1 health-based. Contaminants: Coliform (TCR).
Contaminants: Di(2-ethylhexyl) phthalate, Benzo(a)pyrene, Endothall.
1 health-based. Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Downtown Honolulu's water supply.
Well within EPA limits.
Violation history
Downtown Honolulu's water system has 9 total violations on record, including 3 health-based violations. All violations have been resolved.
Flood & environmental risk
Honolulu County has experienced 9 federally declared disasters since 1974. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include N. Halawa Str Nr Honolulu, Oahu, N. Halawa Str Nr Quar. Stn. At Halawa, Oahu, South Halawa Stream Nr H-3 Freeway, Oahu, Moanalua Stream Nr Kaneohe, Oahu, Kalihi Str Nr Honolulu, Oahu.
Where does Downtown Honolulu's water come from?
Downtown Honolulu's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 3,440 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include N. Halawa Str Nr Honolulu, Oahu (river), N. Halawa Str Nr Quar. Stn. At Halawa, Oahu (river), South Halawa Stream Nr H-3 Freeway, Oahu (river), Moanalua Stream Nr Kaneohe, Oahu (river), Kalihi Str Nr Honolulu, Oahu (river).
What Downtown Honolulu residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Downtown Honolulu's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Flood & disaster history
Honolulu County has experienced 9 federally declared disasters since 1974. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | ND | HI | µg/L | PFAS | Not Detected |
| 8:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | ND | HI | µg/L | PFAS | Not Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | ND | HI | µg/L | PFAS | Not Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | ND | HI | µg/L | PFAS | Not Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | ND | HI | µg/L | PFAS | Not Detected |
| PFPeS | ND | HI | µg/L | PFAS | Not Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
See how Downtown Honolulu compares by contaminant
Explore where Downtown Honolulu ranks among all Hawaii cities for specific contaminants.
Water source & infrastructure
Where Downtown Honolulu's water comes from
Downtown Honolulu's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 3,440 people through 1 water system.
Water bodies near Downtown Honolulu
Downtown Honolulu is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Downtown Honolulu
| System Name | PWSID | Population | Source |
|---|---|---|---|
| THE QUEEN'S MEDICAL CENTER | HI0000312 | 3,440 | GW |
How Downtown Honolulu compares
Full Hawaii rankings →Downtown Honolulu's score of 99.3/100 is above the average of 92/100 among major Hawaii cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Hawaii rankings →About Downtown Honolulu, HI
Wikipedia →Honolulu is the capital and most populous city of the U.S. state of Hawaii, located in the Pacific Ocean. It is the county seat of the consolidated City and County of Honolulu, situated along the southeast coast of the island of Oʻahu. The population of Honolulu was 350,964 at the 2020 census, dropping to an estimated 344,967 by 2024. The Urban Honolulu metropolitan area had an estimated population of just under 1 million residents in 2024 and is the 56th-largest metropolitan area in the nation.
Learn more about your water
Guides and resources related to Downtown Honolulu's water quality findings.
Explore water quality across Honolulu
Frequently asked questions
Is Downtown Honolulu, HI tap water safe to drink?
Downtown Honolulu's water quality earned a grade of A+ (99.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #4 out of 66 cities tested in Hawaii.
What contaminants are in Downtown Honolulu's water?
Lead was measured at 0.0 ppb (90th percentile). No PFAS compounds were detected. 9 violations are on record.
How is Downtown Honolulu's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Downtown Honolulu?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Downtown Honolulu's water come from?
Downtown Honolulu's water is sourced from Groundwater. The city has 1 water system serving approximately 3,440 residents.
What health violations has Downtown Honolulu's water system had?
Downtown Honolulu has 3 health-based violations on record. The most recent violation was recorded in September 2015. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. All health violations have been resolved.
Is Downtown Honolulu's groundwater at risk of contamination?
Downtown Honolulu uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 9 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Downtown Honolulu's water compare to other cities?
Downtown Honolulu ranks #4 out of 66 cities in Hawaii (better than 94% of state cities) and #11 out of 15744 cities nationally (100th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.