Massachusetts Water Quality Report: 1,751 Water-System Violations Mapped to 472 ZIPs
616 water systems · 472 ZIP codes · 1,751 violations
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO
ZipCheckup tracks EPA drinking-water compliance for 616 public water systems serving 472 ZIP codes in Massachusetts. The state record shows 1,751 EPA violations, 105 health-based.
City Water Quality Map: Massachusetts
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Cities with Most Violations in Massachusetts
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Norfolk | 140 | 3 | 11,556 | Details → | |
| 2 | Bolton | 121 | 2 | 5,698 | Details → | |
| 3 | Hudson | 120 | 1 | 19,959 | Details → | |
| 4 | Berlin | 120 | 1 | 3,311 | Details → | |
| 5 | Cohasset | 62 | 2 | 8,358 | Details → | |
| 6 | Halifax | 60 | 1 | 7,734 | Details → | |
| 7 | Westborough | 56 | 1 | 21,591 | Details → | |
| 8 | Upton | 35 | 1 | 7,926 | Details → | |
| 9 | North Dartmouth | 34 | 3 | 21,500 | Details → | |
| 10 | Westport | 34 | 3 | 16,725 | Details → |
Most Common Contaminants in Massachusetts
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 183 | 114 | Yes |
| Consumer Confidence Rule | Reporting | 70 | 52 | No |
| 1,2-Dibromo-3-Chloropropane | Organic | 43 | 28 | No |
| Ethylene Dibromide | Organic | 43 | 28 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 40 | 26 | Yes |
| Nitrate | Inorganic | 34 | 30 | No |
| Groundwater Rule | Treatment Technique | 33 | 9 | No |
| Tetrachloroethylene | Organic | 30 | 14 | Yes |
| Di(2-ethylhexyl) phthalate | Organic | 25 | 22 | No |
| Endrin | Organic | 24 | 21 | No |
Water Quality Overview
Massachusetts has 616 community water systems represented across 472 directly mapped ZIP records. The associated city records cover approximately 6,970,892 people. The available records contain 1,751 EPA violations, including 105 health-based violations.
Health-based violations account for 6% 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 | 105 | 6.0% |
| Monitoring/Reporting | 1,646 | 94.0% |
| Total | 1,751 | 100% |
Health-based violations are MCL, MRDL (disinfectant) and treatment-technique violations. 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 | Violations | Water Systems | Population |
|---|---|---|---|---|
| 1 | Norfolk | 140 | 3 | 11,556 |
| 2 | Bolton | 121 | 2 | 5,698 |
| 3 | Hudson | 120 | 1 | 19,959 |
| 4 | Berlin | 120 | 1 | 3,311 |
| 5 | Cohasset | 62 | 2 | 8,358 |
| 6 | Halifax | 60 | 1 | 7,734 |
| 7 | Westborough | 56 | 1 | 21,591 |
| 8 | Upton | 35 | 1 | 7,926 |
| 9 | North Dartmouth | 34 | 3 | 21,500 |
| 10 | Westport | 34 | 3 | 16,725 |
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.
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Massachusetts:
| Year | Health-based violations |
|---|---|
| 2021 | 51 |
| 2022 | 13 |
| 2023 | 15 |
| 2024 | 13 |
| 2025 | 10 |
| 2026 | 1 |
Health-based violations have decreased from 51 in 2021 to 1 in 2026, 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 |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 183 | 114 | Yes |
| Consumer Confidence Rule | Reporting | 70 | 52 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 40 | 26 | Yes |
| Nitrate | Inorganic | 34 | 30 | No |
| Tetrachloroethylene | Organic | 30 | 14 | Yes |
| Di(2-ethylhexyl) phthalate | Organic | 25 | 22 | No |
| Atrazine | Organic | 24 | 21 | No |
| 1,2,4-Trichlorobenzene | Organic | 23 | 11 | No |
| cis-1,2-Dichloroethylene | Organic | 23 | 11 | No |
| Xylenes, Total | Organic | 23 | 11 | No |
How to Check Your Water in Massachusetts
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the separate Home Safety Score is a multi-source index
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 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 are EPA violations of a Maximum Contaminant Level (MCL), a Maximum Residual Disinfectant Level (MRDL) or a required treatment technique - the enforceable standards designed to protect human health. Massachusetts has 105 such violations across its water systems. Not all violations cause illness; review each violation type and duration to understand possible health implications.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grades summarize ZipCheckup's scoring inputs; review the underlying records for specific 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?
Records for 616 community water systems mapped to ZIPs in Massachusetts show 1,751 reported violations, including 105 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many violations are on record for water systems serving Massachusetts?
Massachusetts has 1,751 EPA violations on record across 472 ZIP codes; 105 are classified as health-based violations. The remainder are monitoring or reporting violations.
Which city in Massachusetts has the worst water quality?
Norfolk, MA has the most recorded EPA violations (140) among the cities with mapped water systems in Massachusetts in our data. Check your water supplier's report and test your tap water for the most accurate picture of your local water quality.
Which city in Massachusetts has the best water quality?
Violation records vary by water system across Massachusetts. Check individual city reports for details.
What contaminants are found in Massachusetts drinking water?
EPA regulates over 90 drinking-water contaminants nationally; water systems in Massachusetts monitor those applicable to each system, which can include lead, copper, nitrate, disinfection byproducts, and bacteria. The most common violations vary by region - check your ZIP code for contaminant-specific data.