Boston Water and Sewer Commission (mwra)
Boston, Massachusetts · PWSID: MA3035000
Boston Water Quality Summary
Boston Water and Sewer Commission (mwra) supplies drinking water to about 675,647 people in Boston, Massachusetts, and draws from surface water (rivers, lakes, or reservoirs), which requires fuller treatment for runoff, sediment, and microbial risk. On the IsWaterSafe scale it earns a good Water Safety Score of 87 out of 100 (Grade B), a composite of its EPA SDWIS violation and contaminant record.
EPA records show 1 health-based violation for this system. A health-based violation means a contaminant exceeded its legal EPA limit, the most serious category in the Safe Drinking Water Act. The system has 1 enforcement action on file in response.
Across the single substance sampled, none exceeded its EPA limit. Combined Filter Effluent sits highest relative to its ceiling, detected at 0.5 NTU against an MCL of 1 NTU (sampled November 2020) — within the legal limit.
The most pressing open issue is a health-based violation involving Combined Filter Effluent, beginning November 2020 and still open in EPA records.
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Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| Combined Filter Effluent | 0.5 NTU | 1 NTU | Within Limit | Nov 1, 2020 |
Violation History
Frequently Asked Questions
Boston Water and Sewer Commission (mwra) has a Water Safety Score of B (87/100). The system serves 675,647 people and has 1 health violation on record. Check the contaminant table above for specific detected substances.
Boston Water and Sewer Commission (mwra) has 0 contaminant exceedances above EPA health guidelines. See the full contaminant detection table above for all tested substances and their levels relative to legal limits and health guidelines.
The Water Safety Score (0-100, grades A through F) is based on contaminant levels relative to legal limits, health guideline exceedances, violation history, and enforcement actions. Higher scores indicate fewer concerns.
If your water system has violations, request the Consumer Confidence Report from your utility, consider getting an independent water test from a certified lab, and look into certified water filters for specific contaminants of concern. For lead, run cold water for 30 seconds before drinking.
Water quality data sourced from EPA's Safe Drinking Water Information System (SDWIS). Safety scores are calculated based on contaminant levels, violations, and enforcement history. This is not a substitute for your utility's official Consumer Confidence Report.
Source: EPA Ground Water and Drinking Water, 2026.