What was found in Helena'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.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 1360 µg/L 14% of the EPA limit 10000 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019
Highest in the city: 10200 µg/L — GRASS LAND ESTATES · 228 people · 2019 | 43/45 | SYR4 |
| Copper | 557 µg/L 43% of the EPA limit 1300 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2018
Highest in the city: 1638 µg/L — BLUE CLOUD SUBDIVISION · 60 people · 2018 | 42/45 | SYR4 |
| Nitrate | 1520 µg/L 15% of the EPA limit 10000 µg/L Highest in the city: MASONIC HOME OF MONTANA · 90 people · 2017 | 1/45 | SYR4 |
| Fluoride | 710 µg/L 18% of the EPA limit 4000 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017
Highest in the city: 990 µg/L — CAMEL MOUNTAIN HOA · 96 people · 2012 | 41/45 | SYR4 |
| Oxamyl | 200 µg/L 100% of the EPA limit 200 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017 | 1/45 | SYR4 |
| Barium | 118.5 µg/L 5.9% of the EPA limit 2000 µg/L Highest in the city: GOLDEN ESTATES HOMEOWNERS ASSOCIATION · 400 people · 2019 | 32/45 | SYR4 |
| Lithium | 78 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2024 | 1/45 | UCMR-5 |
| TTHM | 77.4 µg/L 97% of the EPA limit 80 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 17/45 | SYR4 |
| Chloroform | 74.4 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 12/45 | SYR4 |
| Total Haloacetic Acids (HAA5) | 71.1 µg/L 118% of the EPA limit, at the 95th percentile of samples — 60 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 10/45 | SYR4 |
| Carbofuran | 40 µg/L 100% of the EPA limit 40 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017 | 1/45 | SYR4 |
| Lead | 8 µg/L 53% of the EPA limit 15 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2018
Highest in the city: 39.2 µg/L — NORTH FORESTVALE HOMEOWNERS · 98 people · 2017 | 38/45 | SYR4 |
| Trichloroacetic Acid | 34 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 3/45 | SYR4 |
| Dichloroacetic Acid | 30.8 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 7/45 | SYR4 |
| Arsenic | 23.2 µg/L 232% of the EPA limit, at the 95th percentile of samples — 10 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 39/45 | SYR4 |
| Chromium | 18.85 µg/L 19% of the EPA limit 100 µg/L Highest in the city: GOLDEN ESTATES HOMEOWNERS ASSOCIATION · 400 people · 2019 | 7/45 | SYR4 |
| Gross Alpha, Excl. Radon And U | 2.2 pCi/L 15% of the EPA limit 15 pCi/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017
Highest in the city: 12.1 pCi/L — RANCHVIEW ESTATES WUA · 250 people · 2016 | 32/45 | SYR4 |
| Bromodichloromethane | 11 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 8/45 | SYR4 |
| Combined Uranium | 2.95 µg/L 9.8% of the EPA limit 30 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017
Highest in the city: 10.85 µg/L — HOLMBERG VILLAGE ESTATES · 225 people · 2019 | 30/45 | SYR4 |
| Gross Beta Particle Activity | 8.4 pCi/L No EPA limit set Highest in the city: BLUE CLOUD SUBDIVISION · 60 people · 2013 | 8/45 | SYR4 |
| Monochloroacetic Acid | 6.88 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 2/45 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 5.66 µg/L 94% of the EPA limit 6 µg/L Highest in the city: GRAND VALLEY ESTATES SUBDIVISION · 50 people · 2015 | 6/45 | SYR4 |
| Selenium | 4.85 µg/L 9.7% of the EPA limit 50 µg/L Highest in the city: GOLDEN ESTATES HOMEOWNERS ASSOCIATION · 400 people · 2019 | 16/45 | SYR4 |
| Bromoform | 1.17 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019
Highest in the city: 4.084 µg/L — MASONIC HOME OF MONTANA · 90 people · 2019 | 10/45 | SYR4 |
| Combined Radium (-226 And -228) | 3.1 pCi/L 62% of the EPA limit 5 pCi/L Highest in the city: NORTH STAR PUD · 715 people · 2016 | 18/45 | SYR4 |
| Dibromochloromethane | 3.045 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 11/45 | SYR4 |
| Benzene | 2.0345 µg/L 41% of the EPA limit 5 µg/L Highest in the city: GOLDEN ESTATES TRAILER COURT · 225 people · 2019 | 1/45 | SYR4 |
| Cadmium | 2 µg/L 40% of the EPA limit 5 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2017 | 1/45 | SYR4 |
| Monobromoacetic Acid | 1.86 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 2/45 | SYR4 |
| Dibromoacetic Acid | 0.9820 µg/L No EPA limit set Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019
Highest in the city: 1.18 µg/L — BLUE CLOUD SUBDIVISION · 60 people · 2017 | 10/45 | SYR4 |
| Antimony, Total | 1 µg/L 17% of the EPA limit 6 µg/L Highest in the city: MCHUGH MOBILE HOME PARK · 490 people · 2017 | 1/45 | SYR4 |
| Picloram | 0.7400 µg/L 0.1% of the EPA limit 500 µg/L Highest in the city: GOLDEN ESTATES HOMEOWNERS ASSOCIATION · 400 people · 2019 | 2/45 | SYR4 |
| trans-1,2-Dichloroethylene | 0.5700 µg/L 0.6% of the EPA limit 100 µg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2019 | 1/45 | SYR4 |
| Mercury | 0.2950 µg/L 15% of the EPA limit 2 µg/L Highest in the city: PARK EVERGREEN TRAILER COURT · 87 people · 2019 | 1/45 | SYR4 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L Main supplier: HELENA WATER SYSTEM · 32,091 people · 2024
Highest in the city: 0.0140 mg/L — SKYVIEW WATER AND SEWER UTILITY · 400 people · 2019 | 44/45 | 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 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 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.