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Tap water quality report

Chinook City of

EPA monitoring tested this supplier for 63 contaminants and detected 16. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

63
contaminants tested
16
detected
1,300
people served
32
health-based violations
Montana rankingsLead in MontanaPFAS in Montana
Water source
Surface water
Ownership
Local government
Counties served
Blaine

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

32
health-based violations
52
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2025-10-01 → 2025-12-31
MCL Health-based Resolved 2025-10-01 → 2025-12-31
MCL Health-based Resolved 2025-10-01 → 2025-12-31
MCL Health-based Resolved 2025-07-01 → 2025-09-30
MCL Health-based Resolved 2025-07-01 → 2025-09-30
MCL Health-based Resolved 2025-07-01 → 2025-09-30
MCL Health-based Resolved 2025-04-01 → 2025-06-30
MCL Health-based Resolved 2025-04-01 → 2025-06-30
MCL Health-based Resolved 2025-04-01 → 2025-06-30
MCL Health-based Resolved 2025-04-01 → 2025-06-30

Other contaminants detected

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 this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Bromodichloromethane
23 µg/L
No EPA limit set
worst single sample: 33 µg/L
41/41 SYR4 2012–2019
Chloroform
54 µg/L
No EPA limit set
worst single sample: 63 µg/L
41/41 SYR4 2012–2019
Dibromochloromethane
12 µg/L
No EPA limit set
worst single sample: 23 µg/L
41/41 SYR4 2012–2019
TTHM
76 µg/L 95%
of the EPA limit 80 µg/L
worst single sample: 93 µg/L
41/41 SYR4 2012–2019
Dichloroacetic Acid
28.4 µg/L
No EPA limit set
worst single sample: 48 µg/L
33/33 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
65.2 µg/L 109%
of the EPA limit, at the 95th percentile of samples — 60 µg/L
worst single sample: 103 µg/L
33/33 SYR4 2012–2019
Trichloroacetic Acid
35.4 µg/L
No EPA limit set
worst single sample: 51 µg/L
33/33 SYR4 2012–2019
Dibromoacetic Acid
2.89 µg/L
No EPA limit set
worst single sample: 6 µg/L
32/33 SYR4 2012–2019
Copper
332.7 µg/L 26%
of the EPA limit 1300 µg/L
worst single sample: 591 µg/L
28/30 SYR4 2012–2018
Monochloroacetic Acid
5.7 µg/L
No EPA limit set
worst single sample: 6.1 µg/L
21/33 SYR4 2012–2019
Nitrate-Nitrite
140 µg/L 1.4%
of the EPA limit 10000 µg/L
 16/16 SYR4 2012–2019
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 13/13 LCR 2024
Lead
23.35 µg/L 156%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
worst single sample: 36 µg/L
12/30 SYR4 2012–2018
Bromoform
3.15 µg/L
No EPA limit set
worst single sample: 4.6 µg/L
11/41 SYR4 2012–2019
Monobromoacetic Acid
1.76 µg/L
No EPA limit set
worst single sample: 1.8 µg/L
9/33 SYR4 2012–2019
Combined Radium (-226 And -228)
3.7 pCi/L 74%
of the EPA limit 5 pCi/L
 1/1 SYR4 2017
47 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DArsenicAtrazineBhc-GammaBenzeneBenzo(A)PyreneChlorobenzeneCarbofuranCarbon TetrachlorideChlordaneCombined UraniumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEndrinEthylbenzeneGross Alpha, Excl. Radon And UHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMethoxychlorOxamylPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
DUNKIN, RHIANNON
Phone
406-357-3160
Email
[email protected]

Frequently asked questions about Chinook City of

Is Chinook City of tap water safe to drink?

EPA monitoring detected 16 contaminants in Chinook City of's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Chinook City of's water?

EPA monitoring detected Bromodichloromethane, Chloroform, Dibromochloromethane, TTHM, Dichloroacetic Acid, and others. The full list with the level and data source for each is above.

How many people does Chinook City of serve?

Chinook City of reports serving 1,300 people in Montana, per its EPA record.

Has Chinook City of had any water quality violations?

The EPA has 52 violations on file for Chinook City of, of which 32 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

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.