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Water Quality Report

Watertown, WI

Jefferson County · 24,111 residents · 2 water systems

13

Contaminants detected

0

PFAS compounds

410

Hardness (mg/L)

0

Above legal limits

3

Above health guidelines

Watertown drinking water comes from groundwater wells. Based on the most recent monitoring data, 13 contaminants have been detected in the water supply, including Lead, Nitrate, Arsenic, Copper, and 9 others. PFAS testing has been conducted with no detections. Water hardness is 410 mg/L (very hard), which can cause scale buildup in appliances and reduce soap effectiveness.

Contaminants detected in Watertown water

Detection does not necessarily mean unsafe levels. See individual reports for concentrations and EPA limits.

Lead0.011 / 0.015 mg/L
73% of EPA limit
Nitrate1 / 10 mg/L
10% of EPA limit
Arsenic0.0025 / 0.01 mg/L
25% of EPA limit
Copper100 / 1300 ug/L
8% of EPA limit
Radium3.8 / 5 pCi/L
77% of EPA limit
Uranium1.2 / 30 ug/L
4% of EPA limit
Gross Alpha Radiation7 / 15 pCi/L
47% of EPA limit
Total Trihalomethanes7.9 / 80 ug/L
10% of EPA limit
Haloacetic Acids (HAA5)3.9 / 60 ug/L
6% of EPA limit
Nickel0.0034 mg/L
UnregulatedInorganic
Selenium0.0013 / 0.05 mg/L
3% of EPA limit
Fluoride0.34 / 4 mg/L
9% of EPA limit
Barium0.15 / 2 mg/L
8% of EPA limit
PFAS (tested — none detected)
Microplastics (not routinely tested)

Water systems serving Watertown

WATERTOWN WATERWORKS

23,945 servedGroundwater13 contaminants3 above guidelines
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HIDDEN MEADOWS

166 servedGroundwater0 contaminants
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Other cities in Jefferson County

Water quality reports for nearby Wisconsin communities.

Fort AtkinsonIxoniaJeffersonJohnson CreekLake MillsPalmyraWaterloo

Frequently asked questions

Is Watertown, WI tap water safe to drink?
Watertown tap water meets EPA legal standards (Maximum Contaminant Levels). However, 3 contaminants are present above independent health guidelines, which are often stricter than legal limits. 13 contaminants have been detected in the water supply, including Lead, Nitrate, Arsenic, Copper, Radium. View the detailed report for each water system to see specific levels and how they compare to both legal limits and health guidelines.
What contaminants are in Watertown water?
Monitoring has detected 13 contaminants in Watertown's water supply: Lead, Nitrate, Arsenic, Copper, Radium, Uranium, Gross Alpha Radiation, Total Trihalomethanes, Haloacetic Acids (HAA5), Nickel, Selenium, Fluoride, Barium. 3 exceed health guidelines. See individual system reports for concentrations relative to EPA limits.
Does Watertown water have PFAS?
Watertown's water has been tested for PFAS compounds with no detections. Testing was conducted as part of the EPA's Unregulated Contaminant Monitoring Rule (UCMR5) program.
Is Watertown water hard?
Yes. Watertown water has a hardness of 410 mg/L (very hard). Hard water is not a health concern but can cause scale buildup in water heaters and appliances, reduce soap effectiveness, and leave mineral deposits. Water softeners or conditioning systems can address hardness.
Where does Watertown get its drinking water?
Watertown's drinking water comes from groundwater wells that draw from underground aquifers. The water is treated and tested according to Wisconsin DNR and EPA requirements before distribution. Watertown is served by 2 water systems, the largest being WATERTOWN WATERWORKS (serving 23,945 people).

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