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Tap water quality report

Hamilton City of

EPA monitoring tested this supplier for 103 contaminants and detected 19. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

103
contaminants tested
19
detected
5,660
people served
0
health-based violations
Montana rankingsLead in MontanaPFAS in Montana
Water source
Ground water
Ownership
Local government
Counties served
Ravalli

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.

0
health-based violations
17
violations on file
0
still open
ViolationTypeStatusPeriod
MR Monitoring Resolved 2017-12-30
MR Monitoring Resolved 2017-12-30
MR Monitoring Resolved 2012-01-01 → 2012-12-31
MR Monitoring Resolved 2012-01-01 → 2012-12-31
MR Monitoring Resolved 2012-01-01 → 2012-12-31
MR Monitoring Resolved 2011-12-01 → 2011-12-31
MR Monitoring Resolved 2011-12-01 → 2011-12-31
MR Monitoring Resolved 2011-12-01 → 2011-12-31
Other Monitoring Resolved 2006-07-01
Other Monitoring Resolved 2006-07-01

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
PFBS 0.0031 µg/L 1/8 2024

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
Nitrate-Nitrite
2936 µg/L 29%
of the EPA limit 10000 µg/L
worst single sample: 3340 µg/L
72/74 SYR4 2012–2019
Copper
1135 µg/L 87%
of the EPA limit 1300 µg/L
worst single sample: 1330 µg/L
66/67 SYR4 2013–2017
Lead
22.1 µg/L 147%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
worst single sample: 153 µg/L
23/67 SYR4 2013–2017
Lead
0.0010 mg/L 6.7%
of the EPA limit 0.0150 mg/L
 18/18 LCR 2023
Bromodichloromethane
2.92 µg/L
No EPA limit set
worst single sample: 3.8 µg/L
12/18 SYR4 2013–2019
Chloroform
19.61 µg/L
No EPA limit set
worst single sample: 36 µg/L
12/18 SYR4 2013–2019
TTHM
23.565 µg/L 29%
of the EPA limit 80 µg/L
worst single sample: 41 µg/L
12/18 SYR4 2013–2019
Dichloroacetic Acid
3.69 µg/L
No EPA limit set
worst single sample: 3.9 µg/L
7/7 SYR4 2013–2019
Total Haloacetic Acids (HAA5)
5.6 µg/L 9.3%
of the EPA limit 60 µg/L
 7/7 SYR4 2013–2019
Trichloroacetic Acid
2.39 µg/L
No EPA limit set
worst single sample: 2.6 µg/L
7/7 SYR4 2013–2019
Arsenic
2 µg/L 20%
of the EPA limit 10 µg/L
 5/14 SYR4 2013–2017
Combined Radium (-226 And -228)
4.56 pCi/L 91%
of the EPA limit 5 pCi/L
worst single sample: 4.7 pCi/L
5/6 SYR4 2013–2017
Combined Uranium
2.85 µg/L 9.5%
of the EPA limit 30 µg/L
worst single sample: 3 µg/L
4/6 SYR4 2013–2017
Dibromochloromethane
1.216 µg/L
No EPA limit set
worst single sample: 1.3 µg/L
4/18 SYR4 2013–2019
Fluoride
200 µg/L 5%
of the EPA limit 4000 µg/L
 4/4 SYR4 2013
Gross Alpha, Excl. Radon And U
4.05 pCi/L 27%
of the EPA limit 15 pCi/L
worst single sample: 4.1 pCi/L
3/6 SYR4 2013–2017
Barium
50 µg/L 2.5%
of the EPA limit 2000 µg/L
 1/4 SYR4 2013
Dibromoacetic Acid
0.5700 µg/L
No EPA limit set
 1/7 SYR4 2013–2019
84 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromoformChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEndrinEthylbenzeneHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNetfosaaNfdhaNmefosaaOxamylPfbaPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
LEWIS, STEPHANIE
Phone
406-363-6717

Frequently asked questions about Hamilton City of

Is Hamilton City of tap water safe to drink?

EPA monitoring detected 19 contaminants in Hamilton 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 Hamilton City of's water?

EPA monitoring detected Nitrate-Nitrite, Copper, Lead, Lead, Bromodichloromethane, and others. The full list with the level and data source for each is above.

How many people does Hamilton City of serve?

Hamilton City of reports serving 5,660 people in Montana, per its EPA record.

Has Hamilton City of had any water quality violations?

The EPA has 17 violations on file for Hamilton City of, of which 0 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.