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Tap water quality report

Boulder, MT

EPA monitoring detected 17 contaminants across the 1 water supplier serving Boulder. 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.

1
water supplier
1,400
people served
17
contaminants found
Montana rankings Lead in Montana PFAS in Montana

What was found in Boulder'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
Copper
861.55 µg/L 66%
of the EPA limit 1300 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2018
1/1 SYR4
Nitrate-Nitrite
770 µg/L 7.7%
of the EPA limit 10000 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Fluoride
200 µg/L 5%
of the EPA limit 4000 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Combined Uranium
6 µg/L 20%
of the EPA limit 30 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
TTHM
5.65 µg/L 7.1%
of the EPA limit 80 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Gross Alpha, Excl. Radon And U
4.625 pCi/L 31%
of the EPA limit 15 pCi/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
3.45 µg/L 5.8%
of the EPA limit 60 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Chloroform
2.865 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Gross Beta Particle Activity
2.59 pCi/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2013
1/1 SYR4
Dichloroacetic Acid
2.45 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Bromodichloromethane
2.05 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Lead
1.85 µg/L 12%
of the EPA limit 15 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2018
1/1 SYR4
Dibromochloromethane
1.335 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Trichloroacetic Acid
1.243 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Arsenic
1 µg/L 10%
of the EPA limit 10 µg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Dibromoacetic Acid
0.4970 µg/L
No EPA limit set
Main supplier: BOULDER CITY OF · 1,400 people · 2019
1/1 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: BOULDER CITY OF · 1,400 people · 2024
1/1 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 Boulder

SupplierPopulation served
BOULDER CITY OF 1,400

Frequently asked questions about Boulder tap water

Is Boulder tap water safe to drink?

EPA testing detected 17 contaminants in the water serving Boulder. 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 Boulder?

1 public water supplier report drinking-water monitoring for Boulder, Montana to the EPA. Each is listed above with its population served.

What contaminants are in Boulder's water?

The contaminants EPA monitoring detected in Boulder include Copper, Nitrate-Nitrite, Fluoride, Combined Uranium, TTHM. 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.