Union County, Ohio
12 ZIP codes · Avg score 54/100 · Grade D · Updated 2026-06-03
Union County's 12 ZIP codes show a poor compliance record — repeated MCL exceedances have kept the county in the bottom tier for water safety.
How Union County Compares
How Union County Compares
Union County scores 6 points below the Ohio state average (60/100) and 14 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Union County, Ohio
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.7 (asthma 10.4%, diabetes 11%)
Estimated additional annual cost per homeowner: $1,686, driven primarily by flood
Infrastructure: 0.434% avg pipe failure probability, 82% of ZIPs at high risk
75.5% of homes built before 1978 (lead paint era)
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,686
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
21,513 housing units in Union County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Union County
Remediation costs are relatively manageable for most homeowners in Union County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Union County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Union County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | RICHWOOD VILLAGE PWS | 2,316 | 10 |
| 2 | Del-Company Water Company, Inc. | 150,000 | 10 |
| 3 | MARYSVILLE CITY PWS | 25,571 | 0 |
| 4 | Rosedale Bible Institute | 175 | 0 |
| 5 | NORTH LEWISBURG VILLAGE PWS | 1,850 | 0 |
9 total water systems serve Union County.
All ZIP Codes in Union County
12 ZIP codes tracked in Union County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 43045 | Milford Center | 70 | B | 0 | $232K |
| 2 | 43041 | Marysville | 66 | C | 0 | — |
| 3 | 43040 | Marysville | 65 | C | 0 | $276K |
| 4 | 43344 | Richwood | 64 | C | 10 (1 health) | $218K |
| 5 | 43358 | West Mansfield | 62 | C | 0 | $204K |
| 6 | 43029 | Irwin | 57 | C | 0 | $242K |
| 7 | 43036 | Magnetic Springs | 53 | D | 0 | $121K |
| 8 | 43066 | Radnor | 53 | D | 0 | $317K |
| 9 | 43007 | Broadway | 40 | D | 0 | $178K |
| 10 | 43077 | Unionville Center | 40 | D | 0 | $178K |
| 11 | 43332 | La Rue | 40 | D | 0 | $123K |
| 12 | 43342 | Prospect | 40 | D | 0 | $169K |
Recommended Buyer Guides for Union County
Editorial-only picks, screened against the EPA detections on file.
- Best Lead Paint Test Kits — 75.5% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Union County, Ohio
Overview
Union County in Ohio covers 12 ZIP codes with an average Home Safety Score of D (54/100).
1 of 12 ZIP codes have recorded EPA violations. 1 health-based violation have been documented.
← Back to Ohio water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.
What You Can Do
Union County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
75.5% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.