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Tap water quality report

Koyukuk, AK

EPA monitoring detected 12 contaminants across the 1 water supplier serving Koyukuk. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
85
people served
12
contaminants found
Alaska rankings Lead in Alaska PFAS in Alaska

What was found in Koyukuk's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Copper
336.5 µg/L 26%
of the EPA limit 1300 µg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2017
1/1 SYR4
TTHM
118.7 µg/L 148%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
103.2 µg/L 172%
of the EPA limit, at the 95th percentile of samples — 60 µg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Chloroform
99.18 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Trichloroacetic Acid
63.84 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Dichloroacetic Acid
38.22 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Bromodichloromethane
15.48 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Lead
5.75 µg/L 38%
of the EPA limit 15 µg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2017
1/1 SYR4
Monochloroacetic Acid
3.09 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Dibromochloromethane
1.873 µg/L
No EPA limit set
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2019
1/1 SYR4
Arsenic
1.6 µg/L 16%
of the EPA limit 10 µg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2016
1/1 SYR4
Lead
0.0055 mg/L 37%
of the EPA limit 0.0150 mg/L
Main supplier: KOYUKUK SAFEWATER FACILITY · 85 people · 2025
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 95th percentile of the system's samples — 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 Koyukuk

SupplierPopulation served
KOYUKUK SAFEWATER FACILITY 85

Frequently asked questions about Koyukuk tap water

Is Koyukuk tap water safe to drink?

EPA testing detected 12 contaminants in the water serving Koyukuk. 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 Koyukuk?

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

What contaminants are in Koyukuk's water?

The contaminants EPA monitoring detected in Koyukuk include Copper, TTHM, Total Haloacetic Acids (HAA5), Chloroform, Trichloroacetic Acid. The full list, with the level at the main supplier 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.