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Tap water quality report

Wailuku, HI

EPA monitoring detected 21 contaminants across the 1 water supplier serving Wailuku. A detection doesn't automatically mean the water is unsafe — see the highest level found for each below, with its EPA source and period.

1
water supplier
74,511
people served
21
contaminants found
Hawaii rankings Lead in Hawaii PFAS in Hawaii

What was found in Wailuku'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
3200 µg/L 32%
of the EPA limit 10000 µg/L
 1/1 SYR4
Nitrate-Nitrite
3200 µg/L 32%
of the EPA limit 10000 µg/L
 1/1 SYR4
Fluoride
480 µg/L 12%
of the EPA limit 4000 µg/L
 1/1 SYR4
Copper
50 µg/L 3.8%
of the EPA limit 1300 µg/L
 1/1 SYR4
TTHM
35 µg/L 44%
of the EPA limit 80 µg/L
 1/1 SYR4
Bromoform
24 µg/L
No EPA limit set
 1/1 SYR4
Chloroform
20 µg/L
No EPA limit set
 1/1 SYR4
Total Haloacetic Acids (HAA5)
18 µg/L 30%
of the EPA limit 60 µg/L
 1/1 SYR4
Barium
14 µg/L 0.7%
of the EPA limit 2000 µg/L
 1/1 SYR4
Selenium
12 µg/L 24%
of the EPA limit 50 µg/L
 1/1 SYR4
Dichloroacetic Acid
9.3 µg/L
No EPA limit set
 1/1 SYR4
Dibromochloromethane
9.2 µg/L
No EPA limit set
 1/1 SYR4
Bromodichloromethane
9 µg/L
No EPA limit set
 1/1 SYR4
Trichloroacetic Acid
8.6 µg/L
No EPA limit set
 1/1 SYR4
Lead
5.5 µg/L 37%
of the EPA limit 15 µg/L
 1/1 SYR4
Chromium
4.7 µg/L 4.7%
of the EPA limit 100 µg/L
 1/1 SYR4
Dibromoacetic Acid
3.9 µg/L
No EPA limit set
 1/1 SYR4
Gross Beta Particle Activity
3.4 pCi/L
No EPA limit set
 1/1 SYR4
Gross Alpha, Excl. Radon And U
2.9 pCi/L 19%
of the EPA limit 15 pCi/L
 1/1 SYR4
Di(2-ethylhexyl) Phthalate
1.5 µg/L 25%
of the EPA limit 6 µg/L
 1/1 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 1/1 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 Wailuku

SupplierPopulation served
WAILUKU 74,511

Frequently asked questions about Wailuku tap water

Is Wailuku tap water safe to drink?

EPA testing detected 21 contaminants in the water serving Wailuku. 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 Wailuku?

1 public water supplier report drinking-water monitoring for Wailuku, Hawaii to the EPA. Each is listed above with its population served.

What contaminants are in Wailuku's water?

The contaminants EPA monitoring detected in Wailuku include Nitrate, Nitrate-Nitrite, Fluoride, Copper, TTHM. 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.