What was found in ZIP 57201
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 3200 µg/L 32% of the EPA limit 10000 µg/L Highest in the ZIP: SIOUX RURAL WATER SYSTEM · 4,280 people · 2019 | 1/3 | SYR4 |
| Copper | 65.5 µg/L 5% of the EPA limit 1300 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2018
Highest in the ZIP: 970 µg/L — GRANT-ROBERTS RURAL WATER SYSTEM · 5,050 people · 2019 | 3/3 | SYR4 |
| TTHM | 72.55 µg/L 91% of the EPA limit 80 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2019
Highest in the ZIP: 108.9 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019 | 3/3 | SYR4 |
| Barium | 20.2 µg/L 1% of the EPA limit 2000 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2012
Highest in the ZIP: 103.275 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 21.765 µg/L 36% of the EPA limit 60 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2019
Highest in the ZIP: 80.04 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019 | 3/3 | SYR4 |
| Nitrite | 60 µg/L 6% of the EPA limit 1000 µg/L Highest in the ZIP: GRANT-ROBERTS RURAL WATER SYSTEM · 5,050 people · 2017 | 1/3 | SYR4 |
| Lithium | 12.4 µg/L No EPA limit set Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2025
Highest in the ZIP: 55.7 µg/L — GRANT-ROBERTS RURAL WATER SYSTEM · 5,050 people · 2023 | 3/3 | UCMR-5 |
| Chromium | 1.5 µg/L 1.5% of the EPA limit 100 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2012
Highest in the ZIP: 9.66 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013 | 3/3 | SYR4 |
| Lead | 2.155 µg/L 14% of the EPA limit 15 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2018
Highest in the ZIP: 8.785 µg/L — GRANT-ROBERTS RURAL WATER SYSTEM · 5,050 people · 2019 | 3/3 | SYR4 |
| Gross Alpha, Excl. Radon And U | 6.735 pCi/L 45% of the EPA limit 15 pCi/L Highest in the ZIP: SIOUX RURAL WATER SYSTEM · 4,280 people · 2019 | 1/3 | SYR4 |
| Arsenic | 4 µg/L 40% of the EPA limit 10 µg/L Highest in the ZIP: GRANT-ROBERTS RURAL WATER SYSTEM · 5,050 people · 2013 | 2/3 | SYR4 |
| Selenium | 0.9000 µg/L 1.8% of the EPA limit 50 µg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2012
Highest in the ZIP: 2.78 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013 | 3/3 | SYR4 |
| Antimony, Total | 0.3900 µg/L 6.5% of the EPA limit 6 µg/L Highest in the ZIP: SIOUX RURAL WATER SYSTEM · 4,280 people · 2013 | 1/3 | SYR4 |
| Lead | 0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2024
Highest in the ZIP: 0.0040 mg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2025 | 3/3 | 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.
Water suppliers serving ZIP 57201
| Supplier | State | Population served |
|---|---|---|
| WATERTOWN MUNICIPAL UTILITIES | SD | 23,230 |
| GRANT-ROBERTS RURAL WATER SYSTEM | SD | 5,050 |
| SIOUX RURAL WATER SYSTEM | SD | 4,280 |
Frequently asked questions about ZIP 57201 tap water
Is the tap water in ZIP 57201 safe to drink?
EPA testing detected 14 contaminants across the water suppliers serving ZIP 57201. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 57201?
3 public water suppliers report EPA drinking-water monitoring for ZIP 57201. Each is listed above with its population served.
What contaminants are in ZIP 57201's water?
EPA monitoring detected Nitrate, Copper, TTHM, Barium, Total Haloacetic Acids (HAA5), and others across this ZIP's suppliers. The full list with levels and sources is above.