Massachusetts Water Quality Report: 893 Violations Across 695 ZIPs
761 water systems · 695 ZIP codes · 893 violations · Updated 2026-05-31
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified: 2026-05-31
City Water Quality Map: Massachusetts
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Violation Trend
EPA violations across all water systems in Massachusetts.
Cities with Most Violations in Massachusetts
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Boston | A | 114 | 4 | 3,335,937 | Details → |
| 2 | Springfield | B | 40 | 3 | 168,055 | Details → |
| 3 | Boxford | D | 37 | 3 | 313 | Details → |
| 4 | Andover | D | 25 | 1 | 36,569 | Details → |
| 5 | Attleboro | C | 23 | 2 | 47,088 | Details → |
| 6 | Boxborough | C | 23 | 5 | 2,073 | Details → |
| 7 | Wrentham | C | 21 | 3 | 12,792 | Details → |
| 8 | Bridgewater | B | 18 | 2 | 31,435 | Details → |
| 9 | Barre | C | 18 | 2 | 4,212 | Details → |
| 10 | Worcester | C | 16 | 5 | 206,887 | Details → |
Cities with Best Water Quality in Massachusetts
| # | City | Grade | Score | Systems | Population |
|---|---|---|---|---|---|
| 1 | Chelsea | A | 88/100 | 2 | 2,698,319 |
Most Common Contaminants in Massachusetts
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | 151 | 106 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 62 | 50 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 54 | 24 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 40 | 32 | Yes |
| Contaminant 1039 | Other | 31 | 29 | No |
| Contaminant 1032 | Other | 25 | 22 | No |
| Contaminant 1011 | Other | 22 | 8 | Yes |
| Lead and Copper Rule | Treatment Technique | 21 | 8 | No |
| Lead | Inorganic | 19 | 14 | Yes |
| Contaminant 2400 | Other | 18 | 15 | No |
Water Quality Overview
Massachusetts has 761 community water systems serving approximately 33,954,045 people across 695 ZIP codes. These systems have accumulated 893 EPA violations, including 148 health-based violations.
Health-based violations account for 17% of all violations in Massachusetts. These violations indicate contaminant levels that may pose direct risks to human health, as opposed to monitoring or reporting failures.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 148 | 16.6% |
| Monitoring/Reporting | 745 | 83.4% |
| Total | 893 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report — these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Massachusetts have the highest number of EPA violations:
| Rank | City | Grade | Violations | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Boston | A | 114 | 4 | 3,335,937 |
| 2 | Springfield | B | 40 | 3 | 168,055 |
| 3 | Boxford | D | 37 | 3 | 313 |
| 4 | Andover | D | 25 | 1 | 36,569 |
| 5 | Attleboro | C | 23 | 2 | 47,088 |
| 6 | Boxborough | C | 23 | 5 | 2,073 |
| 7 | Wrentham | C | 21 | 3 | 12,792 |
| 8 | Bridgewater | B | 18 | 2 | 31,435 |
| 9 | Barre | C | 18 | 2 | 4,212 |
| 10 | Worcester | C | 16 | 5 | 206,887 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Cities with Best Water Quality
These Massachusetts cities maintain Grade A water with zero violations:
| Rank | City | Grade | Score | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Chelsea | A | 88/100 | 2 | 2,698,319 |
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Massachusetts:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 76 | 76 |
| 2022 | 59 | 59 |
| 2023 | 52 | 52 |
| 2024 | 36 | 36 |
| 2025 | 9 | 9 |
Violations have decreased from 76 in 2021 to 9 in 2025, suggesting improving compliance across Massachusetts.
Most Common Contaminants
The following contaminants have caused the most violations across Massachusetts water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | 151 | 106 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 62 | 50 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 54 | 24 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 40 | 32 | Yes |
| Lead and Copper Rule | Treatment Technique | 21 | 8 | No |
| Lead | Inorganic | 19 | 14 | Yes |
| Chlorine residual | Disinfectant | 15 | 6 | Yes |
| Barium | Inorganic | 15 | 8 | Yes |
| Copper | Inorganic | 8 | 8 | No |
| Gross Beta | Radionuclides | 8 | 1 | Yes |
How to Check Your Water in Massachusetts
Enter your ZIP code on ZipCheckup for detailed water system data including contaminant levels, violation history, and safety scores
Request your CCR — every water utility must provide an annual Consumer Confidence Report
Get a home test — certified kits ($20-$50) or professional lab tests ($150-$400)
Consider filtration — NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken 2,386 enforcement actions against water systems in Massachusetts. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
What are EPA violations?
Health-based violations mean a contaminant was detected above the EPA's Maximum Contaminant Level (MCL) — the legal limit designed to protect human health. Massachusetts has 148 such violations across its water systems. Not all violations cause illness, but repeated exceedances increase risk, especially for children and immunocompromised individuals.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grade A means few or no violations; Grade F indicates persistent or serious issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Massachusetts?
Massachusetts has 761 community water systems with 893 recorded EPA violations, including 148 health-based. Water quality varies by city and ZIP code — check your specific location for detailed results.
How many water violations does Massachusetts have?
Massachusetts has 893 total EPA violations across 695 ZIP codes. 148 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in Massachusetts has the worst water quality?
Boston, MA has the most EPA violations among major cities in Massachusetts with 114 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in Massachusetts has the best water quality?
Chelsea, MA ranks among the best for water quality in Massachusetts with a grade of A. Multiple cities in Massachusetts maintain strong EPA compliance records.
What contaminants are found in Massachusetts drinking water?
Massachusetts water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. The most common violations vary by region — check your ZIP code for contaminant-specific data.