What was found in Corwin Springs'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 |
|---|---|---|---|
| Copper | 2088 µg/L 161% of the EPA limit, at the 95th percentile of samples — 1300 µg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2018 | 5/5 | SYR4 |
| Fluoride | 300 µg/L 7.5% of the EPA limit 4000 µg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2019
Highest in the city: 980 µg/L — SPHINX MOUNTAIN MB HM PK · 52 people · 2019 | 5/5 | SYR4 |
| Nitrate-Nitrite | 820 µg/L 8.2% of the EPA limit 10000 µg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2019 | 5/5 | SYR4 |
| Barium | 90 µg/L 4.5% of the EPA limit 2000 µg/L Highest in the city: SPHINX MOUNTAIN MB HM PK · 52 people · 2019 | 3/5 | SYR4 |
| Combined Uranium | 22.99 µg/L 77% of the EPA limit 30 µg/L Highest in the city: RANCH HEADQUARTERS · 85 people · 2019 | 3/5 | SYR4 |
| Lead | 4.25 µg/L 28% of the EPA limit 15 µg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2018
Highest in the city: 16.55 µg/L — RANCH HEADQUARTERS · 85 people · 2018 | 4/5 | SYR4 |
| Gross Alpha, Excl. Radon And U | 12.145 pCi/L 81% of the EPA limit 15 pCi/L Highest in the city: SPHINX MOUNTAIN MB HM PK · 52 people · 2017 | 3/5 | SYR4 |
| TTHM | 11.66 µg/L 15% of the EPA limit 80 µg/L Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Arsenic | 7.85 µg/L 78% of the EPA limit 10 µg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2019
Highest in the city: 9 µg/L — RANCH HEADQUARTERS · 85 people · 2019 | 5/5 | SYR4 |
| Chromium | 9 µg/L 9% of the EPA limit 100 µg/L Highest in the city: SPHINX MOUNTAIN MB HM PK · 52 people · 2019 | 1/5 | SYR4 |
| Combined Radium (-226 And -228) | 1.9 pCi/L 38% of the EPA limit 5 pCi/L Main supplier: EAST GATE WORK CAMP · 208 people · 2016
Highest in the city: 4.8 pCi/L — CINNABAR THE · 175 people · 2018 | 4/5 | SYR4 |
| Dibromochloromethane | 3.97 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Bromodichloromethane | 3.43 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Chloroform | 3.18 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Total Haloacetic Acids (HAA5) | 2.65 µg/L 4.4% of the EPA limit 60 µg/L Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Bromoform | 2 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Dichloroacetic Acid | 1.2 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Dibromoacetic Acid | 1.081 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Toluene | 0.8200 µg/L 0.1% of the EPA limit 1000 µg/L Highest in the city: SPHINX MOUNTAIN MB HM PK · 52 people · 2019 | 1/5 | SYR4 |
| Trichloroacetic Acid | 0.7300 µg/L No EPA limit set Highest in the city: GOLDEN AGE VILLAGE · 180 people · 2019 | 1/5 | SYR4 |
| Mercury | 0.1000 µg/L 5% of the EPA limit 2 µg/L Highest in the city: SPHINX MOUNTAIN MB HM PK · 52 people · 2019 | 1/5 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: EAST GATE WORK CAMP · 208 people · 2024
Highest in the city: 0.0150 mg/L — CINNABAR THE · 175 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 Corwin Springs
| Supplier | Population served |
|---|---|
| EAST GATE WORK CAMP | 208 |
| GOLDEN AGE VILLAGE | 180 |
| CINNABAR THE | 175 |
| RANCH HEADQUARTERS | 85 |
| SPHINX MOUNTAIN MB HM PK | 52 |
Frequently asked questions about Corwin Springs tap water
Is Corwin Springs tap water safe to drink?
EPA testing detected 22 contaminants in the water serving Corwin Springs. 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 Corwin Springs?
5 public water suppliers report drinking-water monitoring for Corwin Springs, Montana to the EPA. Each is listed above with its population served.
What contaminants are in Corwin Springs's water?
The contaminants EPA monitoring detected in Corwin Springs include Copper, Fluoride, Nitrate-Nitrite, Barium, Combined Uranium. 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.