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Tap water quality report

Watertown, WI

EPA monitoring detected 20 contaminants across the 3 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.

3
water suppliers
24,142
people served
20
contaminants found
Wisconsin rankings Lead in Wisconsin PFAS in Wisconsin

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
1890 µg/L 19%
of the EPA limit 10000 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
1/3 SYR4
Nitrate-Nitrite
1340 µg/L 13%
of the EPA limit 10000 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
1/3 SYR4
Fluoride
1239.5 µg/L 31%
of the EPA limit 4000 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
3/3 SYR4
Copper
150 µg/L 12%
of the EPA limit 1300 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2017
Highest in the city: 885 µg/L — HICKORY HILL PARK LLC · 31 people · 2018
3/3 SYR4
Barium
147.5 µg/L 7.4%
of the EPA limit 2000 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
3/3 SYR4
TTHM
16.905 µg/L 21%
of the EPA limit 80 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
Highest in the city: 25.334 µg/L — HIDDEN MEADOWS · 166 people · 2019
2/3 SYR4
Chloroform
8.065 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
Highest in the city: 19 µg/L — HIDDEN MEADOWS · 166 people · 2019
2/3 SYR4
Lead
16.9 µg/L 113%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2017
3/3 SYR4
Gross Alpha, Excl. Radon And U
6.64 pCi/L 44%
of the EPA limit 15 pCi/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
2/3 SYR4
Total Haloacetic Acids (HAA5)
6.0095 µg/L 10%
of the EPA limit 60 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
2/3 SYR4
Bromodichloromethane
5.3 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
2/3 SYR4
Combined Radium (-226 And -228)
3.9672 pCi/L 79%
of the EPA limit 5 pCi/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
Highest in the city: 4.4546 pCi/L — HIDDEN MEADOWS · 166 people · 2018
3/3 SYR4
Dichloroacetic Acid
3.7 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
2/3 SYR4
Arsenic
2.1 µg/L 21%
of the EPA limit 10 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
Highest in the city: 3 µg/L — HICKORY HILL PARK LLC · 31 people · 2018
2/3 SYR4
Trichloroacetic Acid
2.26 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
Highest in the city: 2.58 µg/L — HIDDEN MEADOWS · 166 people · 2019
2/3 SYR4
Dibromochloromethane
2.56 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
2/3 SYR4
Dibromoacetic Acid
0.7260 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
2/3 SYR4
Monobromoacetic Acid
0.5980 µg/L
No EPA limit set
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2019
1/3 SYR4
Combined Uranium
0.4580 µg/L 1.5%
of the EPA limit 30 µg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2018
1/3 SYR4
Lead
0.0110 mg/L 73%
of the EPA limit 0.0150 mg/L
Main supplier: WATERTOWN WATERWORKS · 23,945 people · 2024
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. 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 WATERWORKS 23,945
HIDDEN MEADOWS 166
HICKORY HILL PARK LLC 31

Frequently asked questions about Watertown tap water

Is Watertown tap water safe to drink?

EPA testing detected 20 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?

3 public water suppliers report drinking-water monitoring for Watertown, Wisconsin 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, Nitrate-Nitrite, Fluoride, Copper, 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.