Mercer County, Illinois
13 ZIP codes · Avg score 58/100 · Grade C · Updated 2026-06-03
Water safety in Mercer County is uneven — some of its 13 ZIP codes meet standards cleanly while others carry documented violations.
How Mercer County Compares
How Mercer County Compares
Mercer County scores 3 points below the Illinois state average (61/100) and 10 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Mercer County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 14.2 (asthma 10.3%, diabetes 12.4%)
Estimated additional annual cost per homeowner: $1,105, driven primarily by energy_code_gap
Infrastructure: 0.462% avg pipe failure probability, 77% of ZIPs at high risk
81.7% of homes built before 1978 (lead paint era)
Violation History (2022–2024)
→ Stable trendEPA violation counts by year across Mercer County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 2 violations. Past 5 years: 3 total (3 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
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: $1,105
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
7,451 housing units in Mercer 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 Mercer County
Remediation costs are relatively manageable for most homeowners in Mercer 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 Mercer 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 Mercer County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | JOY | 377 | 7 |
| 2 | New Windsor | 740 | 7 |
| 3 | Unity Water Corporation | 93 | 6 |
| 4 | Sherrard | 785 | 5 |
| 5 | Fyre Lake Water Company | 760 | 5 |
15 total water systems serve Mercer County.
All ZIP Codes in Mercer County
13 ZIP codes tracked in Mercer County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 61231 | Aledo | 70 | B | 1 | $141K |
| 2 | 61486 | Viola | 69 | C | 2 | $126K |
| 3 | 61476 | Seaton | 67 | C | 3 | $127K |
| 4 | 61263 | Matherville | 66 | C | 0 | $136K |
| 5 | 61279 | Reynolds | 66 | C | 0 | $165K |
| 6 | 61466 | North Henderson | 66 | C | 1 | $90K |
| 7 | 61260 | Joy | 60 | C | 7 | $84K |
| 8 | 61281 | Sherrard | 59 | C | 5 | $223K |
| 9 | 61465 | New Windsor | 57 | C | 7 (1 health) | $110K |
| 10 | 61442 | Keithsburg | 53 | D | 3 | $65K |
| 11 | 61276 | Preemption | 40 | D | 0 | — |
| 12 | 61928 | Gays | 40 | D | 0 | $118K |
| 13 | 62465 | Strasburg | 40 | D | 0 | $150K |
Recommended Buyer Guides for Mercer County
Eight risk categories drive the selection — PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback — and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.
- Best Lead Paint Test Kits — 81.7% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Mercer County, Illinois
Overview
Mercer County in Illinois covers 13 ZIP codes with an average Home Safety Score of C (58/100).
8 of 13 ZIP codes have recorded EPA violations. 1 health-based violation have been documented.
← Back to Illinois 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.