What was found in ZIP 02421
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| TTHM | 21.4 µg/L 27% of the EPA limit 80 µg/L Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Chloroform | 17.2 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 15.26 µg/L 25% of the EPA limit 60 µg/L Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Dichloroacetic Acid | 12.78 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 3.825 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Monochloroacetic Acid | 2.8525 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Trichloroacetic Acid | 1.8525 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Dibromochloromethane | 1.19 µg/L No EPA limit set Highest in the ZIP: HANSCOM AFB · 11,789 people · 2019 | 1/2 | SYR4 |
| Lead | 0.0018 mg/L 12% of the EPA limit 0.0150 mg/L Main supplier: LEXINGTON WATER DEPT. (MWRA) · 34,074 people · 2025
Highest in the ZIP: 0.0048 mg/L — HANSCOM AFB · 11,789 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.
Water suppliers serving ZIP 02421
| Supplier | State | Population served |
|---|---|---|
| LEXINGTON WATER DEPT. (MWRA) | MA | 34,074 |
| HANSCOM AFB | MA | 11,789 |
Frequently asked questions about ZIP 02421 tap water
Is the tap water in ZIP 02421 safe to drink?
EPA testing detected 9 contaminants across the water suppliers serving ZIP 02421. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 02421?
2 public water suppliers report EPA drinking-water monitoring for ZIP 02421. Each is listed above with its population served.
What contaminants are in ZIP 02421's water?
EPA monitoring detected TTHM, Chloroform, Total Haloacetic Acids (HAA5), Dichloroacetic Acid, Bromodichloromethane, and others across this ZIP's suppliers. The full list with levels and sources is above.