Ohio Water Quality Report: 4,553 Violations Across 907 ZIPs
1,815 water systems · 907 ZIP codes · 4,553 violations · Updated
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified:
ZipCheckup tracks EPA drinking-water compliance for 1,815 public water systems serving 907 ZIP codes in Ohio. The state record shows 4,553 EPA violations, 695 health-based.
City Water Quality Map: Ohio
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 Ohio.
Cities with Most Violations in Ohio
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Rayland | 58 | 5 | 3,288 | Details → | |
| 2 | Saint Clairsville | 55 | 5 | 16,422 | Details → | |
| 3 | Flushing | 41 | 4 | 2,576 | Details → | |
| 4 | Cadiz | 39 | 5 | 4,814 | Details → | |
| 5 | Dillonvale | 38 | 4 | 2,647 | Details → | |
| 6 | Loveland | 36 | 5 | 56,854 | Details → | |
| 7 | Nashport | 35 | 5 | 6,502 | Details → | |
| 8 | Lockbourne | 35 | 5 | 2,188 | Details → | |
| 9 | Akron | 34 | 12 | 263,720 | Details → | |
| 10 | Martins Ferry | 34 | 5 | 7,918 | Details → |
Most Common Contaminants in Ohio
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 1,828 | 584 | No |
| Stage 2 DBP Rule | Treatment Technique | 798 | 386 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 518 | 185 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 415 | 245 | Yes |
| Lead and Copper Rule | Treatment Technique | 335 | 185 | No |
| Stage 1 DBP Rule | Treatment Technique | 322 | 194 | Yes |
| Fecal Coliform | Microbiological | 136 | 78 | Yes |
| Contaminant 0700 | Other | 42 | 27 | Yes |
| Barium | Inorganic | 40 | 19 | Yes |
| Lead | Inorganic | 29 | 26 | No |
Water Quality Overview
Ohio has 1,815 community water systems represented across 907 directly mapped ZIP records. The associated city records cover approximately 11,527,207 people. The available records contain 4,553 EPA violations, including 695 health-based violations.
Health-based violations account for 15% of all violations in Ohio. 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 | 695 | 15.3% |
| Monitoring/Reporting | 3,858 | 84.7% |
| Total | 4,553 | 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 Ohio have the highest number of EPA violations:
| Rank | City | Violations | Water Systems | Population |
|---|---|---|---|---|
| 1 | Rayland | 58 | 5 | 3,288 |
| 2 | Saint Clairsville | 55 | 5 | 16,422 |
| 3 | Flushing | 41 | 4 | 2,576 |
| 4 | Cadiz | 39 | 5 | 4,814 |
| 5 | Dillonvale | 38 | 4 | 2,647 |
| 6 | Loveland | 36 | 5 | 56,854 |
| 7 | Nashport | 35 | 5 | 6,502 |
| 8 | Lockbourne | 35 | 5 | 2,188 |
| 9 | Akron | 34 | 12 | 263,720 |
| 10 | Martins Ferry | 34 | 5 | 7,918 |
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 Ohio:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 44 | 44 |
| 2022 | 146 | 146 |
| 2023 | 118 | 118 |
| 2024 | 442 | 442 |
| 2025 | 233 | 233 |
Violations have increased from 44 in 2021 to 233 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 Ohio water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 1,828 | 584 | No |
| Stage 2 DBP Rule | Treatment Technique | 798 | 386 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 518 | 185 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 415 | 245 | Yes |
| Lead and Copper Rule | Treatment Technique | 335 | 185 | No |
| Stage 1 DBP Rule | Treatment Technique | 322 | 194 | Yes |
| Fecal Coliform | Microbiological | 136 | 78 | Yes |
| Barium | Inorganic | 40 | 19 | Yes |
| Lead | Inorganic | 29 | 26 | No |
| E. coli | Microbiological | 23 | 13 | Yes |
How to Check Your Water in Ohio
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 7,165 enforcement actions against water systems in Ohio. 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. Ohio has 695 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 Ohio?
Ohio has 1,815 community water systems with 4,553 recorded EPA violations, including 695 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many water violations does Ohio have?
Ohio has 4,553 total EPA violations across 907 ZIP codes. 695 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in Ohio has the worst water quality?
Rayland, OH has the most EPA violations among major cities in Ohio with 58 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in Ohio has the best water quality?
Several cities in Ohio maintain excellent EPA compliance. Check individual city reports for details.
What contaminants are found in Ohio drinking water?
Ohio 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.