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Tap water quality report

Honolulu, HI

EPA monitoring detected 15 contaminants across the 2 water suppliers serving Honolulu. A detection doesn't automatically mean the water is unsafe — see the highest level found for each below, with its EPA source and period.

2
water suppliers
23,396
people served
15
contaminants found
Hawaii rankings Lead in Hawaii PFAS in Hawaii

What was found in Honolulu's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
2000 µg/L 20%
of the EPA limit 10000 µg/L
 1/2 SYR4
Nitrate-Nitrite
2000 µg/L 20%
of the EPA limit 10000 µg/L
 1/2 SYR4
Copper
210 µg/L 16%
of the EPA limit 1300 µg/L
 1/2 SYR4
Fluoride
100 µg/L 2.5%
of the EPA limit 4000 µg/L
 1/2 SYR4
Bromoform
11.8 µg/L
No EPA limit set
 2/2 SYR4
TTHM
11.8 µg/L 15%
of the EPA limit 80 µg/L
 2/2 SYR4
Barium
3.9 µg/L 0.2%
of the EPA limit 2000 µg/L
 1/2 SYR4
Dibromoacetic Acid
1.9 µg/L
No EPA limit set
 1/2 SYR4
Total Haloacetic Acids (HAA5)
1.9 µg/L 3.2%
of the EPA limit 60 µg/L
 1/2 SYR4
Monobromoacetic Acid
1.7 µg/L
No EPA limit set
 1/2 SYR4
Tetrachloroethylene
1.4 µg/L 28%
of the EPA limit 5 µg/L
 1/2 SYR4
Lead
0.8500 µg/L 5.7%
of the EPA limit 15 µg/L
 1/2 SYR4
Dibromochloromethane
0.5300 µg/L
No EPA limit set
 1/2 SYR4
1,2-DIBROMO-3-CHLOROPROPANE
0.0120 µg/L 6%
of the EPA limit 0.2000 µg/L
 1/2 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 2/2 LCR
Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Honolulu

SupplierPopulation served
WAHIAWA 23,348
WOODLANDS AT NUUANU 48

Frequently asked questions about Honolulu tap water

Is Honolulu tap water safe to drink?

EPA testing detected 15 contaminants in the water serving Honolulu. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Honolulu?

2 public water suppliers report drinking-water monitoring for Honolulu, Hawaii to the EPA. Each is listed above with its population served.

What contaminants are in Honolulu's water?

The contaminants EPA monitoring detected in Honolulu include Nitrate, Nitrate-Nitrite, Copper, Fluoride, Bromoform. The full list, with the highest level found and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.