Grundy County, Illinois
11 ZIP codes · Avg score 56/100 · Grade C · Updated 2026-06-03
Safe water is the norm for most of Grundy County's 11 ZIP codes — but a notable subset have documented violations that push the grade to the middle tier.
How Grundy County Compares
How Grundy County Compares
Grundy County scores 5 points below the Illinois state average (61/100) and 12 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Grundy County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.2 (asthma 10.1%, diabetes 10.4%)
Estimated additional annual cost per homeowner: $1,969, driven primarily by flood
Infrastructure: 0.419% avg pipe failure probability, 64% of ZIPs at high risk
62.8% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
→ Stable trendEPA violation counts by year across Grundy County water systems. Health-based shown in red, total in blue.
Peak year: 2021 with 12 violations. Past 5 years: 21 total (21 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: $1,969
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
23,597 housing units in Grundy 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 Grundy County
Remediation costs are relatively manageable for most homeowners in Grundy 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 Grundy 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 Grundy County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Coal City | 5,749 | 38 |
| 2 | Prairie Oaks Ests Homeowners Assn | 107 | 20 |
| 3 | Gardner | 1,361 | 16 |
| 4 | Kinsman | 99 | 15 |
| 5 | Braceville | 800 | 10 |
23 total water systems serve Grundy County.
All ZIP Codes in Grundy County
11 ZIP codes tracked in Grundy County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 60407 | Braceville | 66 | C | 8 (1 health) | $178K |
| 2 | 60444 | Mazon | 65 | C | 1 | $220K |
| 3 | 60474 | South Wilmington | 64 | C | 6 | $166K |
| 4 | 60424 | Gardner | 63 | C | 2 | $192K |
| 5 | 60437 | Kinsman | 61 | C | 5 | $169K |
| 6 | 60447 | Minooka | 60 | C | 1 | $295K |
| 7 | 60470 | Ransom | 53 | D | 0 | $114K |
| 8 | 60479 | Verona | 53 | D | 0 | $214K |
| 9 | 60416 | Coal City | 47 | D | 20 (5 health) | $223K |
| 10 | 60450 | Morris | 45 | D | 9 | $267K |
| 11 | 60420 | Dwight | 41 | D | 10 (1 health) | $162K |
Recommended Buyer Guides for Grundy County
Federal and certification sources drive the ordering: EPA monitoring data, NSF certifications, FEMA flood maps, and CDC lead guidance — guides surface only when county data warrants them.
- Best Lead Paint Test Kits — 62.8% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- 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 Grundy County, Illinois
Overview
Grundy County in Illinois covers 11 ZIP codes with an average Home Safety Score of C (56/100).
9 of 11 ZIP codes have recorded EPA violations. 7 health-based violations 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.