What was found in Casper'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 | 3000 µg/L 30% of the EPA limit 10000 µg/L Highest in the city: BROKEN WRENCH LLC · 30 people · 2018 | 2/12 | SYR4 |
| Copper | 930.6 µg/L 72% of the EPA limit 1300 µg/L Main supplier: CASPER, CITY OF · 59,000 people · 2017
Highest in the city: 1305.5 µg/L — MILE-HI I&S DISTRICT · 48 people · 2019 | 12/12 | SYR4 |
| Fluoride | 400 µg/L 10% of the EPA limit 4000 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Nitrate | 400 µg/L 4% of the EPA limit 10000 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2012 | 1/12 | SYR4 |
| Barium | 100 µg/L 5% of the EPA limit 2000 µg/L Highest in the city: BROKEN WRENCH LLC · 30 people · 2016 | 1/12 | SYR4 |
| Lead | 18.6 µg/L 124% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: CASPER, CITY OF · 59,000 people · 2017
Highest in the city: 25.4 µg/L — NATRONA COUNTY INT'L AIRPORT · 423 people · 2018 | 9/12 | SYR4 |
| TTHM | 19.8 µg/L 25% of the EPA limit 80 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Bromate | 16.4 µg/L 164% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Total Haloacetic Acids (HAA5) | 12.45 µg/L 21% of the EPA limit 60 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Combined Uranium | 10.65 µg/L 36% of the EPA limit 30 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2014 | 1/12 | SYR4 |
| Selenium | 9 µg/L 18% of the EPA limit 50 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Gross Alpha, Excl. Radon And U | 8.7 pCi/L 58% of the EPA limit 15 pCi/L Highest in the city: BROKEN WRENCH LLC · 30 people · 2014 | 2/12 | SYR4 |
| Bromodichloromethane | 7.33 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Dibromochloromethane | 6.965 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Dichloroacetic Acid | 6.6 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Chloroform | 6.51 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Monochloroacetic Acid | 3.575 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Combined Radium (-226 And -228) | 3.345 pCi/L 67% of the EPA limit 5 pCi/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2014 | 2/12 | SYR4 |
| Thallium, Total | 2.7 µg/L 135% of the EPA limit, at the 95th percentile of samples — 2 µg/L Highest in the city: BROKEN WRENCH LLC · 30 people · 2017 | 1/12 | SYR4 |
| Trichloroacetic Acid | 2.44 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Dibromoacetic Acid | 2.4 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 2/12 | SYR4 |
| Bromoform | 1.4 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Monobromoacetic Acid | 1.375 µg/L No EPA limit set Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L Highest in the city: CENTRAL WY REGIONAL WATER SYSTEM JPB · 25 people · 2019 | 1/12 | SYR4 |
| Lead | 0.0010 mg/L 6.7% of the EPA limit 0.0150 mg/L Main supplier: CASPER, CITY OF · 59,000 people · 2023
Highest in the city: 0.0030 mg/L — MILE-HI I&S DISTRICT · 48 people · 2024 | 12/12 | 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 Casper
| Supplier | Population served |
|---|---|
| CASPER, CITY OF | 59,000 |
| VISTA WEST WATER COMPANY | 1,600 |
| NATRONA COUNTY INT'L AIRPORT | 423 |
| TERRACE I MHC | 336 |
| RIVERSIDE MOBILE HOME COURT | 330 |
| HIDDEN HILLS MHP | 324 |
| TERRACE II MHC | 320 |
| GREEN VALLEY MHP | 265 |
| SANDY LAKE ESTATES I&S DISTRICT | 150 |
| MILE-HI I&S DISTRICT | 48 |
| BROKEN WRENCH LLC | 30 |
| CENTRAL WY REGIONAL WATER SYSTEM JPB | 25 |
Frequently asked questions about Casper tap water
Is Casper tap water safe to drink?
EPA testing detected 25 contaminants in the water serving Casper. 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 Casper?
12 public water suppliers report drinking-water monitoring for Casper, Wyoming to the EPA. Each is listed above with its population served.
What contaminants are in Casper's water?
The contaminants EPA monitoring detected in Casper include Nitrate-Nitrite, Copper, Fluoride, Nitrate, Barium. 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.