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Tap water quality report

Watertown, SD

EPA monitoring detected 13 contaminants across the 2 water suppliers serving Watertown. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

2
water suppliers
27,510
people served
13
contaminants found
South Dakota rankings Lead in South Dakota PFAS in South Dakota

What was found in Watertown'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.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
3200 µg/L 32%
of the EPA limit 10000 µg/L
Highest in the city: SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
1/2 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 city: 797.5 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
2/2 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 city: 108.9 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
2/2 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 city: 103.275 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013
2/2 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 city: 80.04 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
2/2 SYR4
Lithium
12.4 µg/L
No EPA limit set
Main supplier: WATERTOWN MUNICIPAL UTILITIES · 23,230 people · 2025
Highest in the city: 52.2 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2023
2/2 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 city: 9.66 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013
2/2 SYR4
Gross Alpha, Excl. Radon And U
6.735 pCi/L 45%
of the EPA limit 15 pCi/L
Highest in the city: SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
1/2 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 city: 6.24 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2019
2/2 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 city: 2.78 µg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2013
2/2 SYR4
Arsenic
2 µg/L 20%
of the EPA limit 10 µg/L
Highest in the city: SIOUX RURAL WATER SYSTEM · 4,280 people · 2013
1/2 SYR4
Antimony, Total
0.3900 µg/L 6.5%
of the EPA limit 6 µg/L
Highest in the city: SIOUX RURAL WATER SYSTEM · 4,280 people · 2013
1/2 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 city: 0.0040 mg/L — SIOUX RURAL WATER SYSTEM · 4,280 people · 2025
2/2 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 Watertown

SupplierPopulation served
WATERTOWN MUNICIPAL UTILITIES 23,230
SIOUX RURAL WATER SYSTEM 4,280

Frequently asked questions about Watertown tap water

Is Watertown tap water safe to drink?

EPA testing detected 13 contaminants in the water serving Watertown. 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 Watertown?

2 public water suppliers report drinking-water monitoring for Watertown, South Dakota to the EPA. Each is listed above with its population served.

What contaminants are in Watertown's water?

The contaminants EPA monitoring detected in Watertown include Nitrate, Copper, TTHM, Barium, Total Haloacetic Acids (HAA5). 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.