What was found in Rapid City's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 10600 µg/L 106% of the EPA limit, in the worst sample — 10000 µg/L | 46/67 | SYR4 |
| Copper | 2160 µg/L 166% of the EPA limit, in the worst sample — 1300 µg/L | 64/67 | SYR4 |
| Fluoride | 1600 µg/L 40% of the EPA limit 4000 µg/L | 49/67 | SYR4 |
| Barium | 554 µg/L 28% of the EPA limit 2000 µg/L | 51/67 | SYR4 |
| Nitrite | 200 µg/L 20% of the EPA limit 1000 µg/L | 2/67 | SYR4 |
| TTHM | 102 µg/L 127% of the EPA limit, in the worst sample — 80 µg/L | 38/67 | SYR4 |
| Total Haloacetic Acids (HAA5) | 70.3 µg/L 117% of the EPA limit, in the worst sample — 60 µg/L | 14/67 | SYR4 |
| Lead | 27 µg/L 180% of the EPA limit, in the worst sample — 15 µg/L | 64/67 | SYR4 |
| Lithium | 23.4 µg/L No EPA limit set | 1/67 | UCMR-5 |
| Gross Alpha, Excl. Radon And U | 17.8 pCi/L 119% of the EPA limit, in the worst sample — 15 pCi/L | 45/67 | SYR4 |
| Selenium | 17 µg/L 34% of the EPA limit 50 µg/L | 5/67 | SYR4 |
| Combined Uranium | 11 µg/L 37% of the EPA limit 30 µg/L | 3/67 | SYR4 |
| Arsenic | 6 µg/L 60% of the EPA limit 10 µg/L | 9/67 | SYR4 |
| Gross Beta Particle Activity | 3.5 pCi/L No EPA limit set | 1/67 | SYR4 |
| Chromium | 2.2 µg/L 2.2% of the EPA limit 100 µg/L | 4/67 | SYR4 |
| Mercury | 0.2000 µg/L 10% of the EPA limit 2 µg/L | 1/67 | SYR4 |
| Lead | 0.0140 mg/L 93% of the EPA limit 0.0150 mg/L | 66/67 | LCR |
| PFHXS | 0.0058 µg/L No EPA limit set | 2/67 | UCMR-5 |
| PFOS | 0.0057 µg/L No EPA limit set | 1/67 | UCMR-5 |
Water suppliers serving Rapid City
The 50 largest of 67 suppliers serving Rapid City, by population served.
Frequently asked questions about Rapid City tap water
Is Rapid City tap water safe to drink?
EPA testing detected 19 contaminants in the water serving Rapid City. 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 Rapid City?
67 public water suppliers report drinking-water monitoring for Rapid City, South Dakota to the EPA. Each is listed above with its population served.
What contaminants are in Rapid City's water?
The contaminants EPA monitoring detected in Rapid City include Nitrate, Copper, Fluoride, Barium, Nitrite. The full list, with the highest level found 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.