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Tap water quality report

West Yellowstone, MT

EPA monitoring detected 15 contaminants across the 4 water suppliers serving West Yellowstone. 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.

4
water suppliers
10,239
people served
15
contaminants found
Montana rankings Lead in Montana PFAS in Montana

What was found in West Yellowstone'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
Fluoride
3502.5 µg/L 88%
of the EPA limit 4000 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2019
4/4 SYR4
Copper
330.2 µg/L 25%
of the EPA limit 1300 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
Highest in the city: 1010 µg/L — HEBGEN LAKE ESTATES CO WATER SEWER DISTR · 230 people · 2019
3/4 SYR4
Nitrate-Nitrite
166.25 µg/L 1.7%
of the EPA limit 10000 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2019
Highest in the city: 644 µg/L — HEBGEN LAKE ESTATES CO WATER SEWER DISTR · 230 people · 2019
4/4 SYR4
Barium
1.105 µg/L 0.1%
of the EPA limit 2000 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
Highest in the city: 79.895 µg/L — YELLOWSTONE HOLIDAY WTR AND SEW DISTRICT · 85 people · 2019
3/4 SYR4
Lithium
70 µg/L
No EPA limit set
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2024
1/4 UCMR-5
Lead
7.545 µg/L 50%
of the EPA limit 15 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
Highest in the city: 27.09 µg/L — YELLOWSTONE HOLIDAY WTR AND SEW DISTRICT · 85 people · 2019
3/4 SYR4
Arsenic
2.495 µg/L 25%
of the EPA limit 10 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2019
Highest in the city: 17.12 µg/L — HEBGEN LAKE ESTATES CO WATER SEWER DISTR · 230 people · 2019
2/4 SYR4
Toluene
10.982 µg/L 1.1%
of the EPA limit 1000 µg/L
Highest in the city: HEBGEN LAKE ESTATES CO WATER SEWER DISTR · 230 people · 2019
1/4 SYR4
Gross Alpha, Excl. Radon And U
1.8 pCi/L 12%
of the EPA limit 15 pCi/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2017
Highest in the city: 5.23 pCi/L — YELLOWSTONE HOLIDAY WTR AND SEW DISTRICT · 85 people · 2019
3/4 SYR4
Combined Radium (-226 And -228)
2.67 pCi/L 53%
of the EPA limit 5 pCi/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2017
3/4 SYR4
Selenium
2.59 µg/L 5.2%
of the EPA limit 50 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
1/4 SYR4
Combined Uranium
2.2 µg/L 7.3%
of the EPA limit 30 µg/L
Highest in the city: YELLOWSTONE HOLIDAY WTR AND SEW DISTRICT · 85 people · 2019
1/4 SYR4
Antimony, Total
0.3780 µg/L 6.3%
of the EPA limit 6 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
2/4 SYR4
Mercury
0.0176 µg/L 0.9%
of the EPA limit 2 µg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2018
1/4 SYR4
Lead
0.0013 mg/L 8.3%
of the EPA limit 0.0150 mg/L
Main supplier: WEST YELLOWSTONE TOWN OF · 9,899 people · 2024
Highest in the city: 0.0130 mg/L — HEBGEN LAKE ESTATES CO WATER SEWER DISTR · 230 people · 2025
4/4 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 West Yellowstone

SupplierPopulation served
WEST YELLOWSTONE TOWN OF 9,899
HEBGEN LAKE ESTATES CO WATER SEWER DISTR 230
YELLOWSTONE HOLIDAY WTR AND SEW DISTRICT 85
FISHERMANS VILLAGE SUBDIVISION 25

Frequently asked questions about West Yellowstone tap water

Is West Yellowstone tap water safe to drink?

EPA testing detected 15 contaminants in the water serving West Yellowstone. 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 West Yellowstone?

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

What contaminants are in West Yellowstone's water?

The contaminants EPA monitoring detected in West Yellowstone include Fluoride, Copper, Nitrate-Nitrite, Barium, Lithium. 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.