What was found in Watertown's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Copper | 3200 µg/L 246% of the EPA limit, in the worst sample — 1300 µg/L | 4/4 | SYR4 |
| Fluoride | 920 µg/L 23% of the EPA limit 4000 µg/L | 1/4 | SYR4 |
| Nitrate | 673.8 µg/L 6.7% of the EPA limit 10000 µg/L | 2/4 | SYR4 |
| Nitrate-Nitrite | 673.8 µg/L 6.7% of the EPA limit 10000 µg/L | 2/4 | SYR4 |
| TTHM | 118.2 µg/L 148% of the EPA limit, in the worst sample — 80 µg/L | 4/4 | SYR4 |
| Chloroform | 87.6 µg/L No EPA limit set | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 69.8 µg/L 116% of the EPA limit, in the worst sample — 60 µg/L | 4/4 | SYR4 |
| Lead | 63.59011 µg/L 424% of the EPA limit, in the worst sample — 15 µg/L | 4/4 | SYR4 |
| Cyanide | 50 µg/L 25% of the EPA limit 200 µg/L | 1/4 | SYR4 |
| Trichloroacetic Acid | 39.7 µg/L No EPA limit set | 3/4 | SYR4 |
| Barium | 31 µg/L 1.6% of the EPA limit 2000 µg/L | 2/4 | SYR4 |
| Dichloroacetic Acid | 28.4 µg/L No EPA limit set | 3/4 | SYR4 |
| 1,2,4-Trichlorobenzene | 24.4 µg/L 35% of the EPA limit 70 µg/L | 1/4 | SYR4 |
| Nitrite | 20 µg/L 2% of the EPA limit 1000 µg/L | 1/4 | SYR4 |
| Bromodichloromethane | 11.5 µg/L No EPA limit set | 4/4 | SYR4 |
| Dibromochloromethane | 5.3 µg/L No EPA limit set | 4/4 | SYR4 |
| Gross Alpha, Excl. Radon And U | 3 pCi/L 20% of the EPA limit 15 pCi/L | 2/4 | SYR4 |
| Monochloroacetic Acid | 2.5 µg/L No EPA limit set | 3/4 | SYR4 |
| Combined Radium (-226 And -228) | 2.27 pCi/L 45% of the EPA limit 5 pCi/L | 2/4 | SYR4 |
| Toxaphene | 2.2 µg/L 73% of the EPA limit 3 µg/L | 1/4 | SYR4 |
| Combined Uranium | 1.49 µg/L 5% of the EPA limit 30 µg/L | 1/4 | SYR4 |
| Dibromoacetic Acid | 1.2 µg/L No EPA limit set | 3/4 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L | 1/4 | SYR4 |
| Chromium | 1 µg/L 1% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| Selenium | 1 µg/L 2% of the EPA limit 50 µg/L | 1/4 | SYR4 |
| Thallium, Total | 1 µg/L 50% of the EPA limit 2 µg/L | 1/4 | SYR4 |
| Bromoform | 0.9000 µg/L No EPA limit set | 3/4 | SYR4 |
| Antimony, Total | 0.8000 µg/L 13% of the EPA limit 6 µg/L | 1/4 | SYR4 |
| 1,1,1-Trichloroethane | 0.5000 µg/L 0.3% of the EPA limit 200 µg/L | 1/4 | SYR4 |
| 1,1,2-Trichloroethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| 1,1-Dichloroethylene | 0.5000 µg/L 7.1% of the EPA limit 7 µg/L | 1/4 | SYR4 |
| 1,2-Dichloroethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| 1,2-Dichloropropane | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Benzene | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Chlorobenzene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| Carbon Tetrachloride | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Dichloromethane | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Ethylbenzene | 0.5000 µg/L 0.1% of the EPA limit 700 µg/L | 1/4 | SYR4 |
| Styrene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| Tetrachloroethylene | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Toluene | 0.5000 µg/L 0.1% of the EPA limit 1000 µg/L | 1/4 | SYR4 |
| Trichloroethylene | 0.5000 µg/L 10% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Vinyl Chloride | 0.5000 µg/L 25% of the EPA limit 2 µg/L | 1/4 | SYR4 |
| cis-1,2-Dichloroethylene | 0.5000 µg/L 0.7% of the EPA limit 70 µg/L | 1/4 | SYR4 |
| O-Dichlorobenzene | 0.5000 µg/L 0.1% of the EPA limit 600 µg/L | 1/4 | SYR4 |
| P-Dichlorobenzene | 0.5000 µg/L 0.7% of the EPA limit 75 µg/L | 1/4 | SYR4 |
| trans-1,2-Dichloroethylene | 0.5000 µg/L 0.5% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| 2,4,5-TP | 0.4400 µg/L 0.9% of the EPA limit 50 µg/L | 1/4 | SYR4 |
| Beryllium, Total | 0.3000 µg/L 7.5% of the EPA limit 4 µg/L | 1/4 | SYR4 |
| Cadmium | 0.3000 µg/L 6% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| 2,4-D | 0.2200 µg/L 0.3% of the EPA limit 70 µg/L | 1/4 | SYR4 |
| Methoxychlor | 0.2200 µg/L 0.5% of the EPA limit 40 µg/L | 1/4 | SYR4 |
| Mercury | 0.2000 µg/L 10% of the EPA limit 2 µg/L | 1/4 | SYR4 |
| Asbestos | 0.1700 MFL 2.4% of the EPA limit 7 MFL | 1/4 | SYR4 |
| Bhc-Gamma | 0.0440 µg/L 22% of the EPA limit 0.2000 µg/L | 1/4 | SYR4 |
| Endrin | 0.0220 µg/L 1.1% of the EPA limit 2 µg/L | 1/4 | SYR4 |
| Lead | 0.0040 mg/L 27% of the EPA limit 0.0150 mg/L | 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 single worst sample on
record — 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 highest level found 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.