What was found in Hopkinton'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 | 2400 µg/L 24% of the EPA limit 10000 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019
Highest in the city: 4300 µg/L — THE PRESERVE AT HOPKINTON CONDO · 80 people · 2019 | 5/6 | SYR4 |
| Fluoride | 200 µg/L 5% of the EPA limit 4000 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2018
Highest in the city: 2355 µg/L — MAILLET WOODS CONDOMINIUMS · 55 people · 2018 | 4/6 | SYR4 |
| Copper | 262.66 µg/L 20% of the EPA limit 1300 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2018 | 4/6 | SYR4 |
| Toluene | 103 µg/L 10% of the EPA limit 1000 µg/L Highest in the city: ESTATES AT HIGHLAND RIDGE · 100 people · 2019 | 2/6 | SYR4 |
| TTHM | 72.3 µg/L 90% of the EPA limit 80 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Chloroform | 38.8 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Combined Uranium | 24.365 µg/L 81% of the EPA limit 30 µg/L Highest in the city: ESTATES AT HIGHLAND RIDGE · 100 people · 2019 | 3/6 | SYR4 |
| Barium | 17.6 µg/L 0.9% of the EPA limit 2000 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2018 | 4/6 | SYR4 |
| Bromodichloromethane | 17.4 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Total Haloacetic Acids (HAA5) | 13.4 µg/L 22% of the EPA limit 60 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Trichloroacetic Acid | 9 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 6.32 µg/L 105% of the EPA limit, at the 95th percentile of samples — 6 µg/L Highest in the city: MAILLET WOODS CONDOMINIUMS · 55 people · 2018 | 1/6 | SYR4 |
| Dibromochloromethane | 5.62 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Dibromoacetic Acid | 2.4275 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Monochloroacetic Acid | 1.979 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Dichloroacetic Acid | 1.95 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Bromoform | 1.85 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Trichloroethylene | 1.325 µg/L 27% of the EPA limit 5 µg/L Highest in the city: ESTATES AT HIGHLAND RIDGE · 100 people · 2019 | 1/6 | SYR4 |
| Asbestos | 0.7800 MFL 11% of the EPA limit 7 MFL Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2012 | 1/6 | SYR4 |
| Monobromoacetic Acid | 0.7600 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| 2,4-D | 0.1580 µg/L 0.2% of the EPA limit 70 µg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2019 | 1/6 | SYR4 |
| Lead | 0.0074 mg/L 49% of the EPA limit 0.0150 mg/L Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025
Highest in the city: 0.0130 mg/L — DEERFIELD ESTATES · 100 people · 2025 | 6/6 | LCR |
| PFOA | 0.0072 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025 | 1/6 | UCMR-5 |
| Pfba | 0.0062 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025 | 1/6 | UCMR-5 |
| Pfpea | 0.0058 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025 | 1/6 | UCMR-5 |
| PFBS | 0.0055 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025 | 1/6 | UCMR-5 |
| Pfhxa | 0.0046 µg/L No EPA limit set Main supplier: HOPKINTON WATER DEPARTMENT · 12,680 people · 2025 | 1/6 | 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 Hopkinton
| Supplier | Population served |
|---|---|
| HOPKINTON WATER DEPARTMENT | 12,680 |
| DEERFIELD ESTATES | 100 |
| ESTATES AT HIGHLAND RIDGE | 100 |
| THE PRESERVE AT HOPKINTON CONDO | 80 |
| MAILLET WOODS CONDOMINIUMS | 55 |
| VILLAGE AT HIGHLAND PARK | 50 |
Frequently asked questions about Hopkinton tap water
Is Hopkinton tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Hopkinton. 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 Hopkinton?
6 public water suppliers report drinking-water monitoring for Hopkinton, Massachusetts to the EPA. Each is listed above with its population served.
What contaminants are in Hopkinton's water?
The contaminants EPA monitoring detected in Hopkinton include Nitrate, Fluoride, Copper, Toluene, 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.