Mercer County Water Quality: 16 Violations (OH)
5 water systems · 4 ZIP codes · Home Safety Score Unavailable · 0 of 9 tracked ZIP records scored · Updated
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified:
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Find the Right Filter →Water Quality Overview
Mercer County has 5 community water systems across 4 directly mapped ZIP records. The systems report serving approximately 20,656 people. The available records contain 16 EPA violations, including 1 health-based violation.
Health-based violations account for 6% of all violations in Mercer County. These violations indicate contaminant levels that may pose direct risks to human health.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 1 | 6.3% |
| Monitoring/Reporting | 15 | 93.8% |
| Total | 16 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report.
Cities with Most Violations
| Rank | City | Violations | Health-Based | ZIP Codes | Population |
|---|---|---|---|---|---|
| 1 | Celina | 12 | 1 | 1 | 20,170 |
| 2 | Saint Henry | 2 | 0 | 1 | 4,099 |
| 3 | Coldwater | 1 | 0 | 1 | 6,343 |
| 4 | Maria Stein | 1 | 0 | 1 | 2,437 |
Most Common Contaminants
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 11 | 3 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 3 | 3 | No |
| Chlorine residual | Disinfectant | 1 | 1 | Yes |
Water Data and the Home Safety Score
This page reports EPA water-system facts without converting the broader Home Safety Score into a drinking-water grade. The county Home Safety grade (unavailable) is a separate multi-source index that also requires PFAS screening, radon, and annual air-quality evidence. Check each ZIP report for the versioned score and its component coverage.
Water Systems in Mercer County
Mercer County is served by 5 community water systems, averaging 0.6 systems per ZIP code. Each system is independently regulated and tested by the EPA. Larger systems serving more people typically have more extensive monitoring requirements.
Water systems in Mercer County source water from a mix of surface water (rivers, reservoirs) and groundwater (wells, aquifers). Source type affects which contaminants are most likely to be detected.
How to Check Your Water in Mercer County
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the Home Safety Score is shown separately with its model version
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) can detect contaminants not covered by routine testing
Consider filtration — NSF-certified filters can address specific contaminants found in your area
Check for lead — homes built before 1986 should test for lead regardless of utility compliance
EPA Enforcement
The EPA and state regulators have taken 24 enforcement actions against water systems in Mercer County. Enforcement actions range from compliance assistance and administrative orders to formal penalties. Systems under enforcement are required to remediate violations and may face ongoing monitoring requirements.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Source publication schedules vary. See the page source and verification fields for available timing evidence.
Water Quality by ZIP Code in Mercer County
Water quality varies across Mercer County's 4 ZIP codes. Check your specific ZIP for detailed contaminant data.
Water facts and the Home Safety Score
This page reports water evidence separately. A broader Home Safety Score is not published here unless the versioned model identity and complete required component coverage are available.
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Find the Right Filter →Frequently Asked Questions
Is the tap water safe in Mercer County, Ohio?
Mercer County has 5 community water systems with 16 recorded EPA violations, including 1 health-based. Water quality varies by ZIP code - check your specific location for detailed results.
How many water violations does Mercer County have?
Mercer County has 16 total EPA violations across 4 directly mapped ZIP records. 1 is health-based.
Which city in Mercer County has the most water violations?
Celina has the most violations in Mercer County with 12 recorded EPA violations across 1 ZIP code.
What contaminants are found in Mercer County water?
Mercer County water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. Check your ZIP code for contaminant-specific data.
How can I test my water in Mercer County?
Contact your local water utility for free or low-cost testing. You can also use a certified home test kit ($20-$50) or hire a certified lab ($150-$400).