Knox County, Illinois
20 ZIP codes · Avg score 57/100 · Grade C · Updated 2026-06-03
Knox County's water quality grade reflects a middle-ground assessment — its 20 ZIP codes range from fully compliant to violation-flagged.
How Knox County Compares
How Knox County Compares
Knox County scores 4 points below the Illinois state average (61/100) and 11 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Knox County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 14.5 (asthma 10.6%, diabetes 13.3%)
Estimated additional annual cost per homeowner: $1,139, driven primarily by energy_code_gap
Infrastructure: 0.459% avg pipe failure probability, 85% of ZIPs at high risk
85.6% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
↑ Worsening trendEPA violation counts by year across Knox County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 5 violations. Past 5 years: 10 total (10 health-based). Health-based violations are rising versus the prior 2-year window — worth closer monitoring.
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: $1,139
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
24,326 housing units in Knox 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 Knox County
Remediation costs are relatively manageable for most homeowners in Knox 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 Knox 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 Knox County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Galesburg | 31,620 | 17 |
| 2 | KNOXVILLE | 3,120 | 16 |
| 3 | Green Meadow Estates of Rockford Llc | 250 | 13 |
| 4 | Henderson | 375 | 12 |
| 5 | Wataga | 965 | 7 |
18 total water systems serve Knox County.
All ZIP Codes in Knox County
20 ZIP codes tracked in Knox County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 61410 | Abingdon | 68 | C | 2 | $93K |
| 2 | 61439 | Henderson | 66 | C | 12 (1 health) | $98K |
| 3 | 61467 | Oneida | 66 | C | 1 | $133K |
| 4 | 61472 | Rio | 66 | C | 0 | $149K |
| 5 | 61414 | Altona | 64 | C | 2 | $122K |
| 6 | 61430 | East Galesburg | 64 | C | 2 | $106K |
| 7 | 61572 | Yates City | 63 | C | 1 | $95K |
| 8 | 61488 | Wataga | 61 | C | 7 (1 health) | $125K |
| 9 | 61448 | Knoxville | 60 | C | 13 (5 health) | $140K |
| 10 | 61458 | Maquon | 60 | C | 4 | $89K |
| 11 | 61485 | Victoria | 60 | C | 2 | $101K |
| 12 | 61489 | Williamsfield | 58 | C | 2 (1 health) | $131K |
| 13 | 61402 | Galesburg | 57 | C | 1 | — |
| 14 | 61423 | Cameron | 53 | D | 0 | $122K |
| 15 | 61428 | Dahinda | 53 | D | 0 | $250K |
| 16 | 61451 | Laura | 53 | D | 0 | $103K |
| 17 | 61401 | Galesburg | 52 | D | 1 | $95K |
| 18 | 61417 | Berwick | 40 | D | 0 | $78K |
| 19 | 61436 | Gilson | 40 | D | 0 | $187K |
| 20 | 61474 | Saint Augustine | 40 | D | 0 | $78K |
Recommended Buyer Guides for Knox County
Designed to find the guide that fits the county, not the other way around — the system reads EPA detections, FEMA hazard layers, and CDC lead-exposure markers, then outputs the categories that resolve those specific risks for households here, with NSF-certified products surfaced when the matching contaminant appears in the local monitoring data.
- Best Lead Paint Test Kits — 85.6% 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
Deep Dive Reports
Detailed analysis for Knox County, Illinois
Overview
Knox County in Illinois covers 20 ZIP codes with an average Home Safety Score of C (57/100).
13 of 20 ZIP codes have recorded EPA violations. 8 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.