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Tap water quality report

Big Arm Water

EPA monitoring tested this supplier for 76 contaminants and detected 10. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

76
contaminants tested
10
detected
116
people served
2
health-based violations
Montana rankingsLead in MontanaPFAS in Montana
Water source
Ground water
Ownership
Native American

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.

2
health-based violations
8
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2017-11-24
TT Health-based Resolved 2017-11-24
MR Monitoring Resolved 2023-10-01
MR Monitoring Resolved 2017-04-01 → 2017-06-30
MR Monitoring Resolved 2017-04-01 → 2017-06-30
MR Monitoring Resolved 2017-04-01 → 2017-06-30
MR Monitoring Resolved 2017-04-01 → 2017-06-30
MR Monitoring Resolved 2017-04-01 → 2017-06-30

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
Copper
253 µg/L 19%
of the EPA limit 1300 µg/L
worst single sample: 280 µg/L
10/10 SYR4 2017
Combined Uranium
14.75 µg/L 49%
of the EPA limit 30 µg/L
worst single sample: 15 µg/L
6/6 SYR4 2016–2018
Gross Alpha, Excl. Radon And U
8.225 pCi/L 55%
of the EPA limit 15 pCi/L
worst single sample: 8.4 pCi/L
6/6 SYR4 2016–2018
Nitrate
440 µg/L 4.4%
of the EPA limit 10000 µg/L
 6/6 SYR4 2016–2018
Lead
0.0010 mg/L 6.7%
of the EPA limit 0.0150 mg/L
 4/4 LCR 2023
Nitrate-Nitrite
448.5 µg/L 4.5%
of the EPA limit 10000 µg/L
worst single sample: 450 µg/L
4/4 SYR4 2016–2019
Lead
1 µg/L 6.7%
of the EPA limit 15 µg/L
 3/10 SYR4 2017
Barium
169 µg/L 8.5%
of the EPA limit 2000 µg/L
worst single sample: 170 µg/L
2/2 SYR4 2016–2018
Combined Radium (-226 And -228)
2.84 pCi/L 57%
of the EPA limit 5 pCi/L
worst single sample: 2.9 pCi/L
2/6 SYR4 2016–2018
Fluoride
268.5 µg/L 6.7%
of the EPA limit 4000 µg/L
worst single sample: 270 µg/L
2/2 SYR4 2016–2018
66 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAntimony, TotalArsenicAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromodichloromethaneBromoformChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneChloroformChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDibromochloromethaneDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNitriteOxamylPentachlorophenolPicloramSeleniumSimazineStyreneTTHMTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
PHILLIPS, REBECCA
Phone
406-675-4491
Email
[email protected]

Frequently asked questions about Big Arm Water

Is Big Arm Water tap water safe to drink?

EPA monitoring detected 10 contaminants in Big Arm Water'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 Big Arm Water's water?

EPA monitoring detected Copper, Combined Uranium, Gross Alpha, Excl. Radon And U, Nitrate, Lead, and others. The full list with the level and data source for each is above.

How many people does Big Arm Water serve?

Big Arm Water reports serving 116 people in Montana, per its EPA record.

Has Big Arm Water had any water quality violations?

The EPA has 8 violations on file for Big Arm Water, of which 2 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.