What was found in Greenwich'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 | 1339 µg/L 13% of the EPA limit 10000 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 2372.5 µg/L — AQUARION-STAMFORD · 119,214 people · 2019 | 4/4 | SYR4 |
| Nitrate-Nitrite | 1285 µg/L 13% of the EPA limit 10000 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 1723.2 µg/L — AQUARION-STAMFORD · 119,214 people · 2019 | 4/4 | SYR4 |
| Fluoride | 916 µg/L 23% of the EPA limit 4000 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019 | 4/4 | SYR4 |
| Copper | 261 µg/L 20% of the EPA limit 1300 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 724.2 µg/L — BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2019 | 4/4 | SYR4 |
| Chlorite | 631.5 µg/L 63% of the EPA limit 1000 µg/L Highest in the city: AQUARION-GREENWICH · 53,297 people · 2019 | 1/4 | SYR4 |
| TTHM | 80.7 µg/L 101% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 84.25 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Chloroform | 63 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 66 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 53.9 µg/L 90% of the EPA limit 60 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 61.25 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Barium | 48.9 µg/L 2.4% of the EPA limit 2000 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 57.8 µg/L — BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2017 | 4/4 | SYR4 |
| Lead | 42.65 µg/L 284% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019 | 4/4 | SYR4 |
| Trichloroacetic Acid | 29 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 31 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Dichloroacetic Acid | 24 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 29 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Bromodichloromethane | 16 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 19 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 4/4 | SYR4 |
| Dibromochloromethane | 3 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 7.06 µg/L — BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2019 | 4/4 | SYR4 |
| Combined Uranium | 4.591 µg/L 15% of the EPA limit 30 µg/L Highest in the city: BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2019 | 1/4 | SYR4 |
| Bromoform | 0.5950 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 4.1 µg/L — BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2019 | 3/4 | SYR4 |
| Monochloroacetic Acid | 2 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 3 µg/L — AQUARION-GREENWICH · 53,297 people · 2019 | 3/4 | SYR4 |
| Dibromoacetic Acid | 1 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019
Highest in the city: 1.685 µg/L — BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) · 567 people · 2019 | 4/4 | SYR4 |
| Monobromoacetic Acid | 1 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2019 | 3/4 | SYR4 |
| PFOA | 0.0109 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 3/4 | UCMR-5 |
| Pfba | 0.0076 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 1/4 | UCMR-5 |
| Pfhxa | 0.0074 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 3/4 | UCMR-5 |
| Pfpea | 0.0067 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 3/4 | UCMR-5 |
| PFOS | 0.0066 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 2/4 | UCMR-5 |
| PFBS | 0.0041 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 1/4 | UCMR-5 |
| Pfhpa | 0.0039 µg/L No EPA limit set Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2024 | 1/4 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: AQUARION-EASTERN FAIRFIELD COUNTY · 351,756 people · 2026 | 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 Greenwich
| Supplier | Population served |
|---|---|
| AQUARION-EASTERN FAIRFIELD COUNTY | 351,756 |
| AQUARION-STAMFORD | 119,214 |
| AQUARION-GREENWICH | 53,297 |
| BRUNSWICK SCHOOL (LOWER & LOWER MIDDLE) | 567 |
Frequently asked questions about Greenwich tap water
Is Greenwich tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Greenwich. 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 Greenwich?
4 public water suppliers report drinking-water monitoring for Greenwich, Connecticut to the EPA. Each is listed above with its population served.
What contaminants are in Greenwich's water?
The contaminants EPA monitoring detected in Greenwich include Nitrate, Nitrate-Nitrite, Fluoride, Copper, Chlorite. 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.