New Hampshire Water Quality Report: 354 Violations Across 124 ZIPs
195 water systems · 124 ZIP codes · 354 violations · Updated
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified:
ZipCheckup tracks EPA drinking-water compliance for 195 public water systems serving 124 ZIP codes in New Hampshire. The state record shows 354 EPA violations, 77 health-based.
City Water Quality Map: New Hampshire
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 New Hampshire.
Cities with Most Violations in New Hampshire
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Merrimack | 25 | 2 | 27,604 | Details → | |
| 2 | Conway | 23 | 4 | 3,930 | Details → | |
| 3 | Center Conway | 23 | 2 | 3,897 | Details → | |
| 4 | North Conway | 23 | 4 | 3,780 | Details → | |
| 5 | Kearsarge | 22 | 1 | 198 | Details → | |
| 6 | Contoocook | 21 | 1 | 5,976 | Details → | |
| 7 | Greenville | 17 | 2 | 3,414 | Details → | |
| 8 | Gilford | 15 | 4 | 7,785 | Details → | |
| 9 | Goffstown | 12 | 5 | 14,013 | Details → | |
| 10 | Madison | 11 | 1 | 1,451 | Details → |
Most Common Contaminants in New Hampshire
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 46 | 25 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 44 | 30 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 33 | 22 | Yes |
| Combined Radium | Radionuclides | 26 | 5 | Yes |
| Lead and Copper Rule | Treatment Technique | 19 | 9 | No |
| Surface Water Treatment Rule | Treatment Technique | 12 | 8 | No |
| Barium | Inorganic | 9 | 7 | Yes |
| Revised Total Coliform Rule | Microbiological | 9 | 6 | No |
| Bromate | Disinfection Byproducts | 7 | 6 | Yes |
| PFOA | PFAS | 5 | 5 | No |
Water Quality Overview
New Hampshire has 195 community water systems represented across 124 directly mapped ZIP records. The associated city records cover approximately 1,131,076 people. The available records contain 354 EPA violations, including 77 health-based violations.
Health-based violations account for 22% of all violations in New Hampshire. 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 | 77 | 21.8% |
| Monitoring/Reporting | 277 | 78.2% |
| Total | 354 | 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 New Hampshire have the highest number of EPA violations:
| Rank | City | Violations | Water Systems | Population |
|---|---|---|---|---|
| 1 | Merrimack | 25 | 2 | 27,604 |
| 2 | Conway | 23 | 4 | 3,930 |
| 3 | Center Conway | 23 | 2 | 3,897 |
| 4 | North Conway | 23 | 4 | 3,780 |
| 5 | Kearsarge | 22 | 1 | 198 |
| 6 | Contoocook | 21 | 1 | 5,976 |
| 7 | Greenville | 17 | 2 | 3,414 |
| 8 | Gilford | 15 | 4 | 7,785 |
| 9 | Goffstown | 12 | 5 | 14,013 |
| 10 | Madison | 11 | 1 | 1,451 |
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 New Hampshire:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 22 | 22 |
| 2022 | 39 | 39 |
| 2023 | 49 | 49 |
| 2024 | 49 | 49 |
| 2025 | 54 | 54 |
Violations have increased from 22 in 2021 to 54 in 2025. This trend warrants monitoring and may reflect expanded testing requirements rather than worsening quality.
Most Common Contaminants
The following contaminants have caused the most violations across New Hampshire water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 46 | 25 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 44 | 30 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 33 | 22 | Yes |
| Combined Radium | Radionuclides | 26 | 5 | Yes |
| Lead and Copper Rule | Treatment Technique | 19 | 9 | No |
| Surface Water Treatment Rule | Treatment Technique | 12 | 8 | No |
| Barium | Inorganic | 9 | 7 | Yes |
| Revised Total Coliform Rule | Microbiological | 9 | 6 | No |
| Bromate | Disinfection Byproducts | 7 | 6 | Yes |
| PFOA | PFAS | 5 | 5 | No |
How to Check Your Water in New Hampshire
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 710 enforcement actions against water systems in New Hampshire. 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. New Hampshire has 77 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 New Hampshire?
New Hampshire has 195 community water systems with 354 recorded EPA violations, including 77 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many water violations does New Hampshire have?
New Hampshire has 354 total EPA violations across 124 ZIP codes. 77 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in New Hampshire has the worst water quality?
Merrimack, NH has the most EPA violations among major cities in New Hampshire with 25 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in New Hampshire has the best water quality?
Several cities in New Hampshire maintain excellent EPA compliance. Check individual city reports for details.
What contaminants are found in New Hampshire drinking water?
New Hampshire 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.