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.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Copper | 237.5 µg/L 18% of the EPA limit 1300 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 1065.8 µg/L — WATERTOWN FIRE DISTRICT · 6,718 people · 2019 | 4/4 | SYR4 |
| Fluoride | 909 µg/L 23% of the EPA limit 4000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Nitrate | 71 µg/L 0.7% of the EPA limit 10000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 673.8 µg/L — WATERTOWN FIRE DISTRICT · 6,718 people · 2019 | 2/4 | SYR4 |
| Nitrate-Nitrite | 69.5 µg/L 0.7% of the EPA limit 10000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 595.65 µg/L — WATERTOWN FIRE DISTRICT · 6,718 people · 2019 | 2/4 | SYR4 |
| TTHM | 83.62 µg/L 105% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 90.7 µg/L — WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 4/4 | SYR4 |
| Chloroform | 34.475 µg/L No EPA limit set Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 79.55 µg/L — WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 54.69 µg/L 91% of the EPA limit 60 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 60.3 µg/L — WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 4/4 | SYR4 |
| Cyanide | 50 µg/L 25% of the EPA limit 200 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Trichloroacetic Acid | 33.95 µg/L No EPA limit set Highest in the city: WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 3/4 | SYR4 |
| Barium | 11.45 µg/L 0.6% of the EPA limit 2000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 30.45 µg/L — WATERTOWN FIRE DISTRICT · 6,718 people · 2019 | 2/4 | SYR4 |
| Dichloroacetic Acid | 26.75 µg/L No EPA limit set Highest in the city: WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 3/4 | SYR4 |
| 1,2,4-Trichlorobenzene | 24.4 µg/L 35% of the EPA limit 70 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Nitrite | 16.4 µg/L 1.6% of the EPA limit 1000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Lead | 15.6 µg/L 104% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 4/4 | SYR4 |
| Bromodichloromethane | 5.62 µg/L No EPA limit set Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 10.6 µg/L — WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 4/4 | SYR4 |
| Dibromochloromethane | 0.7750 µg/L No EPA limit set Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 4.76 µg/L — WATERTOWN WATER & SEWER - WESTGATE · 600 people · 2019 | 4/4 | SYR4 |
| Gross Alpha, Excl. Radon And U | 3 pCi/L 20% of the EPA limit 15 pCi/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 2/4 | SYR4 |
| Combined Radium (-226 And -228) | 2.27 pCi/L 45% of the EPA limit 5 pCi/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2015 | 2/4 | SYR4 |
| Toxaphene | 2.2 µg/L 73% of the EPA limit 3 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Monochloroacetic Acid | 2.115 µg/L No EPA limit set Highest in the city: WATERTOWN WATER & SEWER AUTHORITY · 9,972 people · 2019 | 3/4 | SYR4 |
| Combined Uranium | 1.49 µg/L 5% of the EPA limit 30 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Dibromoacetic Acid | 1.17 µg/L No EPA limit set Highest in the city: WATERTOWN FIRE DISTRICT · 6,718 people · 2019 | 3/4 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Chromium | 1 µg/L 1% of the EPA limit 100 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Selenium | 1 µg/L 2% of the EPA limit 50 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Thallium, Total | 1 µg/L 50% of the EPA limit 2 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Bromoform | 0.5000 µg/L No EPA limit set Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019
Highest in the city: 0.8700 µg/L — WATERTOWN WATER & SEWER - WESTGATE · 600 people · 2019 | 3/4 | SYR4 |
| Antimony, Total | 0.8000 µg/L 13% of the EPA limit 6 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 1,1,1-Trichloroethane | 0.5000 µg/L 0.3% of the EPA limit 200 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 1,1,2-Trichloroethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 1,1-Dichloroethylene | 0.5000 µg/L 7.1% of the EPA limit 7 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 1,2-Dichloroethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 1,2-Dichloropropane | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Benzene | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Chlorobenzene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Carbon Tetrachloride | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Dichloromethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Ethylbenzene | 0.5000 µg/L 0.1% of the EPA limit 700 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Styrene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Tetrachloroethylene | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Toluene | 0.5000 µg/L 0.1% of the EPA limit 1000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Trichloroethylene | 0.5000 µg/L 10% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Vinyl Chloride | 0.5000 µg/L 25% of the EPA limit 2 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| cis-1,2-Dichloroethylene | 0.5000 µg/L 0.7% of the EPA limit 70 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| O-Dichlorobenzene | 0.5000 µg/L 0.1% of the EPA limit 600 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| P-Dichlorobenzene | 0.5000 µg/L 0.7% of the EPA limit 75 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| trans-1,2-Dichloroethylene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 2,4,5-TP | 0.4400 µg/L 0.9% of the EPA limit 50 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Beryllium, Total | 0.3000 µg/L 7.5% of the EPA limit 4 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Cadmium | 0.3000 µg/L 6% of the EPA limit 5 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| 2,4-D | 0.2200 µg/L 0.3% of the EPA limit 70 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Methoxychlor | 0.2200 µg/L 0.5% of the EPA limit 40 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Mercury | 0.2000 µg/L 10% of the EPA limit 2 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Asbestos | 0.1700 MFL 2.4% of the EPA limit 7 MFL Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Bhc-Gamma | 0.0440 µg/L 22% of the EPA limit 0.2000 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Endrin | 0.0220 µg/L 1.1% of the EPA limit 2 µg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2019 | 1/4 | SYR4 |
| Lead | 0.0040 mg/L 27% of the EPA limit 0.0150 mg/L Main supplier: WATERBURY WATER DEPARTMENT · 107,271 people · 2025 | 4/4 | 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
| Supplier | Population served |
|---|---|
| WATERBURY WATER DEPARTMENT | 107,271 |
| WATERTOWN WATER & SEWER AUTHORITY | 9,972 |
| WATERTOWN FIRE DISTRICT | 6,718 |
| WATERTOWN WATER & SEWER - WESTGATE | 600 |
Frequently asked questions about Watertown tap water
Is Watertown tap water safe to drink?
EPA testing detected 57 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?
4 public water suppliers report drinking-water monitoring for Watertown, Connecticut 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 Copper, Fluoride, Nitrate, Nitrate-Nitrite, TTHM. 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.