What was found in Shelby'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 | 60 µg/L 0.6% of the EPA limit 10000 µg/L Main supplier: SHELBY CITY OF · 3,970 people · 2019
Highest in the city: 1371.5 µg/L — OILMONT COUNTY WATER DISTRICT · 300 people · 2019 | 3/5 | SYR4 |
| Copper | 251.65 µg/L 19% of the EPA limit 1300 µg/L Main supplier: SHELBY CITY OF · 3,970 people · 2017
Highest in the city: 289.85 µg/L — ETHRIDGE COUNTY WATER DISTRICT · 70 people · 2017 | 4/5 | SYR4 |
| Fluoride | 200 µg/L 5% of the EPA limit 4000 µg/L Main supplier: SHELBY CITY OF · 3,970 people · 2017
Highest in the city: 208.8 µg/L — DEVON WATER INC · 75 people · 2016 | 3/5 | SYR4 |
| Barium | 152.9 µg/L 7.6% of the EPA limit 2000 µg/L Highest in the city: DEVON WATER INC · 75 people · 2016 | 1/5 | SYR4 |
| TTHM | 94.92 µg/L 119% of the EPA limit, at the 95th percentile of samples — 80 µg/L Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 87.065 µg/L 145% of the EPA limit, at the 95th percentile of samples — 60 µg/L Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Chloroform | 77.025 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Trichloroacetic Acid | 45.34 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 1/5 | SYR4 |
| Dichloroacetic Acid | 42.835 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 1/5 | SYR4 |
| Lead | 4.7 µg/L 31% of the EPA limit 15 µg/L Main supplier: SHELBY CITY OF · 3,970 people · 2017
Highest in the city: 23.1 µg/L — ETHRIDGE COUNTY WATER DISTRICT · 70 people · 2017 | 3/5 | SYR4 |
| Bromodichloromethane | 15 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Lithium | 12 µg/L No EPA limit set Main supplier: SHELBY CITY OF · 3,970 people · 2024 | 1/5 | UCMR-5 |
| Selenium | 7 µg/L 14% of the EPA limit 50 µg/L Highest in the city: OILMONT COUNTY WATER DISTRICT · 300 people · 2012 | 2/5 | SYR4 |
| Gross Alpha, Excl. Radon And U | 4.9 pCi/L 33% of the EPA limit 15 pCi/L Highest in the city: DEVON WATER INC · 75 people · 2013 | 1/5 | SYR4 |
| Dibromochloromethane | 4.283 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Monochloroacetic Acid | 3.4005 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 1/5 | SYR4 |
| Arsenic | 1.9 µg/L 19% of the EPA limit 10 µg/L Highest in the city: DEVON WATER INC · 75 people · 2018 | 1/5 | SYR4 |
| Combined Radium (-226 And -228) | 1.9 pCi/L 38% of the EPA limit 5 pCi/L Main supplier: SHELBY CITY OF · 3,970 people · 2017 | 1/5 | SYR4 |
| Combined Uranium | 1 µg/L 3.3% of the EPA limit 30 µg/L Main supplier: SHELBY CITY OF · 3,970 people · 2017 | 1/5 | SYR4 |
| Dibromoacetic Acid | 0.7944 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 2/5 | SYR4 |
| Monobromoacetic Acid | 0.3570 µg/L No EPA limit set Highest in the city: DEVON WATER INC · 75 people · 2019 | 1/5 | SYR4 |
| Lead | 0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: SHELBY CITY OF · 3,970 people · 2025 | 5/5 | 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 Shelby
| Supplier | Population served |
|---|---|
| SHELBY CITY OF | 3,970 |
| OILMONT COUNTY WATER DISTRICT | 300 |
| NCMRWA NORTH SHELBY | 300 |
| DEVON WATER INC | 75 |
| ETHRIDGE COUNTY WATER DISTRICT | 70 |
Frequently asked questions about Shelby tap water
Is Shelby tap water safe to drink?
EPA testing detected 22 contaminants in the water serving Shelby. 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 Shelby?
5 public water suppliers report drinking-water monitoring for Shelby, Montana to the EPA. Each is listed above with its population served.
What contaminants are in Shelby's water?
The contaminants EPA monitoring detected in Shelby include Nitrate-Nitrite, Copper, Fluoride, Barium, 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.