What was found in Gillette'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 |
|---|---|---|---|
| Fluoride | 1500 µg/L 38% of the EPA limit 4000 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018
Highest in the city: 4600 µg/L — ROZET RANCHETTES I&S DISTRICT · 85 people · 2019 | 33/43 | SYR4 |
| Nitrate-Nitrite | 330 µg/L 3.3% of the EPA limit 10000 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 3100 µg/L — COOK ROAD WATER DISTRICT · 291 people · 2019 | 32/43 | SYR4 |
| Barium | 100 µg/L 5% of the EPA limit 2000 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018
Highest in the city: 709 µg/L — SOUTHFORK ESTATES · 144 people · 2017 | 33/43 | SYR4 |
| Copper | 237.6 µg/L 18% of the EPA limit 1300 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 414.5 µg/L — GREEN VALLEY ESTATES I&S DISTRICT · 140 people · 2018 | 40/43 | SYR4 |
| Cyanide | 130 µg/L 65% of the EPA limit 200 µg/L Highest in the city: STONE GATE ESTATES · 198 people · 2017 | 2/43 | SYR4 |
| Lead | 10 µg/L 67% of the EPA limit 15 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 47.4 µg/L — NICKELSON FARMS WATER COMPANY · 400 people · 2019 | 40/43 | SYR4 |
| TTHM | 13.95 µg/L 17% of the EPA limit 80 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 28 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 39/43 | SYR4 |
| Gross Alpha, Excl. Radon And U | 9.81 pCi/L 65% of the EPA limit 15 pCi/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018
Highest in the city: 14.95 pCi/L — COOK ROAD WATER DISTRICT · 291 people · 2017 | 28/43 | SYR4 |
| Bromoform | 2.61 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 14.23 µg/L — EAGLE RIDGE MHP, LLC · 140 people · 2017 | 37/43 | SYR4 |
| Dibromochloromethane | 4.89 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 10.83 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 38/43 | SYR4 |
| Nitrate | 10 µg/L 0.1% of the EPA limit 10000 µg/L Highest in the city: CEDAR HILLS WATER ASSOCIATION · 258 people · 2014 | 1/43 | SYR4 |
| Combined Uranium | 9.14 µg/L 30% of the EPA limit 30 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018 | 2/43 | SYR4 |
| Selenium | 9 µg/L 18% of the EPA limit 50 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018 | 9/43 | SYR4 |
| Chromium | 8 µg/L 8% of the EPA limit 100 µg/L Highest in the city: EIGHT MILE SUBDIVISION · 120 people · 2017 | 4/43 | SYR4 |
| Bromodichloromethane | 4.49 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 7.21 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 38/43 | SYR4 |
| Combined Radium (-226 And -228) | 2.28 pCi/L 46% of the EPA limit 5 pCi/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018
Highest in the city: 6.88 pCi/L — SOUTHFORK ESTATES · 144 people · 2018 | 29/43 | SYR4 |
| Total Haloacetic Acids (HAA5) | 4.405 µg/L 7.3% of the EPA limit 60 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 5.875 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 37/43 | SYR4 |
| Chloroform | 4.26 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 4.485 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 36/43 | SYR4 |
| Arsenic | 3 µg/L 30% of the EPA limit 10 µg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2018 | 3/43 | SYR4 |
| Dichloroacetic Acid | 2.04 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 3 µg/L — SECTION 4 WATER SYSTEM INCORPORATED · 120 people · 2017 | 21/43 | SYR4 |
| Dibromoacetic Acid | 1.58 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 2.84 µg/L — ROZET RANCHETTES I&S DISTRICT · 85 people · 2017 | 36/43 | SYR4 |
| Trichloroacetic Acid | 0.7400 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019
Highest in the city: 1.9 µg/L — OVERBROOK SUBDIVISION · 66 people · 2017 | 11/43 | SYR4 |
| Xylenes, Total | 1.3 µg/L 0% of the EPA limit 10000 µg/L Highest in the city: NICKELSON FARMS WATER COMPANY · 400 people · 2019 | 4/43 | SYR4 |
| Monochloroacetic Acid | 1.181 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019 | 2/43 | SYR4 |
| Diquat | 0.8400 µg/L 4.2% of the EPA limit 20 µg/L Highest in the city: ANTELOPE VALLEY I&S DISTRICT (AVISD) · 1,280 people · 2017 | 2/43 | SYR4 |
| Monobromoacetic Acid | 0.5670 µg/L No EPA limit set Main supplier: GILLETTE, CITY OF · 32,222 people · 2019 | 2/43 | SYR4 |
| Asbestos | 0.2000 MFL 2.9% of the EPA limit 7 MFL Highest in the city: CEDAR HILLS WATER ASSOCIATION · 258 people · 2015 | 1/43 | SYR4 |
| Lead | 0.0040 mg/L 27% of the EPA limit 0.0150 mg/L Main supplier: GILLETTE, CITY OF · 32,222 people · 2025
Highest in the city: 0.0080 mg/L — FOX RIDGE WATER SYSTEM · 38 people · 2023 | 43/43 | 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 Gillette
Frequently asked questions about Gillette tap water
Is Gillette tap water safe to drink?
EPA testing detected 28 contaminants in the water serving Gillette. 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 Gillette?
43 public water suppliers report drinking-water monitoring for Gillette, Wyoming to the EPA. Each is listed above with its population served.
What contaminants are in Gillette's water?
The contaminants EPA monitoring detected in Gillette include Fluoride, Nitrate-Nitrite, Barium, Copper, Cyanide. 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.