What was found in Sudbury'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 | 6210 µg/L 62% of the EPA limit 10000 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Fluoride | 1100 µg/L 28% of the EPA limit 4000 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2018 | 1/1 | SYR4 |
| Cyanide | 209.5 µg/L 105% of the EPA limit, at the 95th percentile of samples — 200 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Copper | 89.68 µg/L 6.9% of the EPA limit 1300 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| TTHM | 81.865 µg/L 102% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Barium | 51.6 µg/L 2.6% of the EPA limit 2000 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2018 | 1/1 | SYR4 |
| Chloroform | 48.05 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Total Haloacetic Acids (HAA5) | 40.62 µg/L 68% of the EPA limit 60 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Bromodichloromethane | 27.2 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Trichloroacetic Acid | 24 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Dichloroacetic Acid | 17.55 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Dibromochloromethane | 12.1 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Monobromoacetic Acid | 9.075 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Monochloroacetic Acid | 5.865 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Dibromoacetic Acid | 4.63 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Bromoform | 2.17 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| Arsenic | 1.91 µg/L 19% of the EPA limit 10 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2018 | 1/1 | SYR4 |
| Trichloroethylene | 0.7470 µg/L 15% of the EPA limit 5 µg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2019 | 1/1 | SYR4 |
| PFOA | 0.0090 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
| Pfhxa | 0.0060 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
| Pfba | 0.0050 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
| Pfpea | 0.0050 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
| PFBS | 0.0040 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
| Lead | 0.0035 mg/L 23% of the EPA limit 0.0150 mg/L Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | LCR |
| Pfhpa | 0.0030 µg/L No EPA limit set Main supplier: SUDBURY WATER DISTRICT · 18,416 people · 2025 | 1/1 | UCMR-5 |
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 Sudbury
| Supplier | Population served |
|---|---|
| SUDBURY WATER DISTRICT | 18,416 |
Frequently asked questions about Sudbury tap water
Is Sudbury tap water safe to drink?
EPA testing detected 25 contaminants in the water serving Sudbury. 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 Sudbury?
1 public water supplier report drinking-water monitoring for Sudbury, Massachusetts to the EPA. Each is listed above with its population served.
What contaminants are in Sudbury's water?
The contaminants EPA monitoring detected in Sudbury include Nitrate, Fluoride, Cyanide, Copper, 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.