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Tap water quality report

Chinook, MT

EPA monitoring detected 16 contaminants across the 2 water suppliers serving Chinook. 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.

2
water suppliers
1,400
people served
16
contaminants found
Montana rankings Lead in Montana PFAS in Montana

What was found in Chinook'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
332.7 µg/L 26%
of the EPA limit 1300 µg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2018
2/2 SYR4
Nitrate-Nitrite
140 µg/L 1.4%
of the EPA limit 10000 µg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
TTHM
76 µg/L 95%
of the EPA limit 80 µg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Total Haloacetic Acids (HAA5)
65.2 µg/L 109%
of the EPA limit, at the 95th percentile of samples — 60 µg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Chloroform
54 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Trichloroacetic Acid
35.4 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Dichloroacetic Acid
28.4 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Lead
23.35 µg/L 156%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2018
1/2 SYR4
Bromodichloromethane
23 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Dibromochloromethane
12 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Monochloroacetic Acid
5.7 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Combined Radium (-226 And -228)
3.7 pCi/L 74%
of the EPA limit 5 pCi/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2017
1/2 SYR4
Bromoform
3.15 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Dibromoacetic Acid
2.89 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Monobromoacetic Acid
1.76 µg/L
No EPA limit set
Main supplier: CHINOOK CITY OF · 1,300 people · 2019
1/2 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: CHINOOK CITY OF · 1,300 people · 2024
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 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 Chinook

SupplierPopulation served
CHINOOK CITY OF 1,300
PERRYS WATER SERVICE 100

Frequently asked questions about Chinook tap water

Is Chinook tap water safe to drink?

EPA testing detected 16 contaminants in the water serving Chinook. 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 Chinook?

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

What contaminants are in Chinook's water?

The contaminants EPA monitoring detected in Chinook include Copper, Nitrate-Nitrite, TTHM, Total Haloacetic Acids (HAA5), Chloroform. 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.