Warren County, Illinois
6 ZIP codes · Avg score 56/100 · Grade C · Updated 2026-06-03
Water systems across Warren County's 6 ZIP codes produce average compliance results overall — pockets with documented violations exist, and the variation between areas makes ZIP-level lookup the most useful tool for residents here.
How Warren County Compares
How Warren County Compares
Warren 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: Warren County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.9 (asthma 10.4%, diabetes 12.6%)
Estimated additional annual cost per homeowner: $1,287, driven primarily by energy_code_gap
Infrastructure: 0.49% avg pipe failure probability, 83% of ZIPs at high risk
86.2% of homes built before 1978 (lead paint era)
Violation History (2023–2024)
→ Stable trendEPA violation counts by year across Warren County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 1 violation. Past 5 years: 2 total (2 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: $1,287
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
6,929 housing units in Warren 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 Warren County
Water safety remediation is a moderate expense relative to home values. Most homeowners can address issues through staged improvements over time.
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 Warren 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 Warren County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Little Swan Lake Sd | 438 | 11 |
| 2 | Monmouth | 8,902 | 6 |
| 3 | Abingdon | 3,275 | 6 |
| 4 | St Augustine | 119 | 6 |
| 5 | Alexis | 836 | 5 |
8 total water systems serve Warren County.
All ZIP Codes in Warren County
6 ZIP codes tracked in Warren County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 61462 | Monmouth | 69 | C | 6 (1 health) | $101K |
| 2 | 61447 | Kirkwood | 68 | C | 2 | $96K |
| 3 | 61473 | Roseville | 62 | C | 0 | $97K |
| 4 | 61435 | Gerlaw | 53 | D | 0 | — |
| 5 | 61412 | Alexis | 43 | D | 5 | $107K |
| 6 | 61453 | Little York | 40 | D | 5 | $85K |
Recommended Buyer Guides for Warren County
Methodologically, the recommendation order reflects severity in the federal record: contaminants flagged in EPA detection records for this county outrank generic water concerns, FEMA-confirmed hazard ratings shift emergency-related categories upward, and CDC lead-exposure markers govern when lead-test kits and certified filters appear at the top of the list.
- Best Water Filters for Lead — Lead above EPA action level in 1 ZIP code
- Best Lead Paint Test Kits — 86.2% 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 Warren County, Illinois
Overview
Warren County in Illinois covers 6 ZIP codes with an average Home Safety Score of C (56/100).
4 of 6 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.