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Tap water quality report

Big Mountain Water Company

EPA monitoring tested this supplier for 70 contaminants and detected 14. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

70
contaminants tested
14
detected
2,435
people served
7
health-based violations
Montana rankingsLead in MontanaPFAS in Montana
Water source
Ground water
Ownership
Private
Counties served
Flathead

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.

7
health-based violations
483
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2014-10-01 → 2014-10-31
MCL Health-based Resolved 2014-10-01 → 2014-10-31
MCL Health-based Resolved 2014-10-01 → 2014-10-31
MCL Health-based Resolved 2014-10-01 → 2014-10-31
MCL Health-based Resolved 2014-10-01 → 2014-10-31
MCL Health-based Resolved 1994-12-01 → 1994-12-31
MCL Health-based Resolved 1994-07-01 → 1994-07-31
MR Monitoring Resolved 2024-01-01 → 2024-03-31
MR Monitoring Resolved 2024-01-01 → 2024-03-31
MR Monitoring Resolved 2024-01-01 → 2024-03-31

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
443 µg/L 4.4%
of the EPA limit 10000 µg/L
worst single sample: 620 µg/L
39/39 SYR4 2012–2019
Copper
187.7 µg/L 14%
of the EPA limit 1300 µg/L
worst single sample: 270 µg/L
30/30 SYR4 2013–2019
Combined Uranium
23.215 µg/L 77%
of the EPA limit 30 µg/L
worst single sample: 33 µg/L
20/20 SYR4 2013–2019
Lead
5.2 µg/L 35%
of the EPA limit 15 µg/L
worst single sample: 9 µg/L
20/30 SYR4 2013–2019
Lead
0.0070 mg/L 47%
of the EPA limit 0.0150 mg/L
 16/16 LCR 2025
Barium
546 µg/L 27%
of the EPA limit 2000 µg/L
worst single sample: 570 µg/L
9/9 SYR4 2012–2019
Gross Alpha, Excl. Radon And U
8 pCi/L 53%
of the EPA limit 15 pCi/L
worst single sample: 8.4 pCi/L
9/11 SYR4 2013–2019
Nitrate
470 µg/L 4.7%
of the EPA limit 10000 µg/L
 8/8 SYR4 2012
Combined Radium (-226 And -228)
3.45 pCi/L 69%
of the EPA limit 5 pCi/L
worst single sample: 3.5 pCi/L
6/6 SYR4 2013–2019
Arsenic
4.85 µg/L 49%
of the EPA limit 10 µg/L
worst single sample: 5 µg/L
4/15 SYR4 2012–2018
Fluoride
30 µg/L 0.8%
of the EPA limit 4000 µg/L
 4/9 SYR4 2012–2019
Antimony, Total
2 µg/L 33%
of the EPA limit 6 µg/L
 1/9 SYR4 2012–2019
Gross Beta Particle Activity
3.5 pCi/L
No EPA limit set
 1/1 SYR4 2016
Selenium
5 µg/L 10%
of the EPA limit 50 µg/L
 1/9 SYR4 2012–2019
56 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromodichloromethaneBromoformChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChloroformChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDibromochloromethaneDinosebEndrinEthylbenzeneHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNitriteOxamylPentachlorophenolPicloramSimazineStyreneTTHMTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
MAKI, GINA
Phone
406-862-2905

Frequently asked questions about Big Mountain Water Company

Is Big Mountain Water Company tap water safe to drink?

EPA monitoring detected 14 contaminants in Big Mountain Water Company'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 Mountain Water Company's water?

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

How many people does Big Mountain Water Company serve?

Big Mountain Water Company reports serving 2,435 people in Montana, per its EPA record.

Has Big Mountain Water Company had any water quality violations?

The EPA has 483 violations on file for Big Mountain Water Company, of which 7 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.