What was found in Helena's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 11900 µg/L 119% of the EPA limit, in the worst sample — 10000 µg/L | 43/45 | SYR4 |
| Copper | 2020 µg/L 155% of the EPA limit, in the worst sample — 1300 µg/L | 42/45 | SYR4 |
| Nitrate | 1520 µg/L 15% of the EPA limit 10000 µg/L | 1/45 | SYR4 |
| Fluoride | 1000 µg/L 25% of the EPA limit 4000 µg/L | 41/45 | SYR4 |
| Oxamyl | 200 µg/L 100% of the EPA limit 200 µg/L | 1/45 | SYR4 |
| Barium | 120 µg/L 6% of the EPA limit 2000 µg/L | 32/45 | SYR4 |
| TTHM | 99 µg/L 124% of the EPA limit, in the worst sample — 80 µg/L | 17/45 | SYR4 |
| Total Haloacetic Acids (HAA5) | 92 µg/L 153% of the EPA limit, in the worst sample — 60 µg/L | 10/45 | SYR4 |
| Chloroform | 91 µg/L No EPA limit set | 12/45 | SYR4 |
| Lithium | 78 µg/L No EPA limit set | 1/45 | UCMR-5 |
| Lead | 64 µg/L 427% of the EPA limit, in the worst sample — 15 µg/L | 38/45 | SYR4 |
| Dichloroacetic Acid | 49 µg/L No EPA limit set | 7/45 | SYR4 |
| Carbofuran | 40 µg/L 100% of the EPA limit 40 µg/L | 1/45 | SYR4 |
| Trichloroacetic Acid | 40 µg/L No EPA limit set | 3/45 | SYR4 |
| Arsenic | 31 µg/L 310% of the EPA limit, in the worst sample — 10 µg/L | 39/45 | SYR4 |
| Chromium | 19 µg/L 19% of the EPA limit 100 µg/L | 7/45 | SYR4 |
| Gross Alpha, Excl. Radon And U | 12.1 pCi/L 81% of the EPA limit 15 pCi/L | 32/45 | SYR4 |
| Bromodichloromethane | 12 µg/L No EPA limit set | 8/45 | SYR4 |
| Combined Uranium | 11 µg/L 37% of the EPA limit 30 µg/L | 30/45 | SYR4 |
| Gross Beta Particle Activity | 8.4 pCi/L No EPA limit set | 8/45 | SYR4 |
| Monochloroacetic Acid | 8.3 µg/L No EPA limit set | 2/45 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 5.8 µg/L 97% of the EPA limit 6 µg/L | 6/45 | SYR4 |
| Selenium | 5 µg/L 10% of the EPA limit 50 µg/L | 16/45 | SYR4 |
| Bromoform | 4.23 µg/L No EPA limit set | 10/45 | SYR4 |
| Dibromochloromethane | 3.6 µg/L No EPA limit set | 11/45 | SYR4 |
| Combined Radium (-226 And -228) | 3.1 pCi/L 62% of the EPA limit 5 pCi/L | 18/45 | SYR4 |
| Benzene | 2.1 µg/L 42% of the EPA limit 5 µg/L | 1/45 | SYR4 |
| Cadmium | 2 µg/L 40% of the EPA limit 5 µg/L | 1/45 | SYR4 |
| Monobromoacetic Acid | 1.9 µg/L No EPA limit set | 2/45 | SYR4 |
| Dibromoacetic Acid | 1.2 µg/L No EPA limit set | 10/45 | SYR4 |
| Antimony, Total | 1 µg/L 17% of the EPA limit 6 µg/L | 1/45 | SYR4 |
| Picloram | 0.7400 µg/L 0.1% of the EPA limit 500 µg/L | 2/45 | SYR4 |
| trans-1,2-Dichloroethylene | 0.5700 µg/L 0.6% of the EPA limit 100 µg/L | 1/45 | SYR4 |
| Mercury | 0.3000 µg/L 15% of the EPA limit 2 µg/L | 1/45 | SYR4 |
| Lead | 0.0140 mg/L 93% of the EPA limit 0.0150 mg/L | 44/45 | LCR |
Water suppliers serving Helena
Frequently asked questions about Helena tap water
Is Helena tap water safe to drink?
EPA testing detected 35 contaminants in the water serving Helena. 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 Helena?
45 public water suppliers report drinking-water monitoring for Helena, Montana to the EPA. Each is listed above with its population served.
What contaminants are in Helena's water?
The contaminants EPA monitoring detected in Helena include Nitrate-Nitrite, Copper, Nitrate, Fluoride, Oxamyl. The full list, with the highest level found 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.