What was found in Ansonia'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 |
|---|---|---|---|
| Nitrate-Nitrite | 3227.6 µg/L 32% of the EPA limit 10000 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Nitrate | 3102 µg/L 31% of the EPA limit 10000 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Fluoride | 1020 µg/L 26% of the EPA limit 4000 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Nitrite | 442.2 µg/L 44% of the EPA limit 1000 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 1/2 | SYR4 |
| Copper | 270 µg/L 21% of the EPA limit 1300 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 348.5 µg/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| Barium | 246.8 µg/L 12% of the EPA limit 2000 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| TTHM | 81.905 µg/L 102% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Chloroform | 70.9 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 74 µg/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 57.575 µg/L 96% of the EPA limit 60 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Lead | 44.2 µg/L 295% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 31.09 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 21.85 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 13.39 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 14 µg/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| Gross Beta Particle Activity | 8.5 pCi/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 1/2 | SYR4 |
| Monochloroacetic Acid | 6.1 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Combined Radium (-226 And -228) | 1.549 pCi/L 31% of the EPA limit 5 pCi/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 5.68 pCi/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 3.2 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 2/2 | SYR4 |
| Chromium | 1.5 µg/L 1.5% of the EPA limit 100 µg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019 | 1/2 | SYR4 |
| Bromoform | 0.7500 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 1.35 µg/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 0.8000 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2019
Highest in the city: 1 µg/L — AQUARION-VALLEY · 13,080 people · 2019 | 2/2 | SYR4 |
| PFOS | 0.0107 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2024 | 2/2 | UCMR-5 |
| PFOA | 0.0071 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2024
Highest in the city: 0.0081 µg/L — AQUARION-VALLEY · 13,080 people · 2025 | 2/2 | UCMR-5 |
| Pfpea | 0.0031 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2024
Highest in the city: 0.0068 µg/L — AQUARION-VALLEY · 13,080 people · 2025 | 2/2 | UCMR-5 |
| Pfhxa | 0.0049 µg/L No EPA limit set Highest in the city: AQUARION-VALLEY · 13,080 people · 2025 | 1/2 | UCMR-5 |
| PFBS | 0.0035 µg/L No EPA limit set Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2024
Highest in the city: 0.0046 µg/L — AQUARION-VALLEY · 13,080 people · 2025 | 2/2 | UCMR-5 |
| Pfhpa | 0.0036 µg/L No EPA limit set Highest in the city: AQUARION-VALLEY · 13,080 people · 2025 | 1/2 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: REGIONAL WATER AUTHORITY · 418,900 people · 2026
Highest in the city: 0.0011 mg/L — AQUARION-VALLEY · 13,080 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 Ansonia
| Supplier | Population served |
|---|---|
| REGIONAL WATER AUTHORITY | 418,900 |
| AQUARION-VALLEY | 13,080 |
Frequently asked questions about Ansonia tap water
Is Ansonia tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Ansonia. 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 Ansonia?
2 public water suppliers report drinking-water monitoring for Ansonia, Connecticut to the EPA. Each is listed above with its population served.
What contaminants are in Ansonia's water?
The contaminants EPA monitoring detected in Ansonia include Nitrate-Nitrite, Nitrate, Fluoride, Nitrite, Copper. 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.