Washington County, Illinois
9 ZIP codes · Avg score 69/100 · Grade C · Updated 2026-06-03
For most households in Washington County, the 9 tracked ZIP codes show adequate but uneven water quality.
How Washington County Compares
How Washington County Compares
Washington County scores 8 points above the Illinois state average (61/100) and 1 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Washington County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.5 (asthma 10.2%, diabetes 11.7%)
Estimated additional annual cost per homeowner: $879, driven primarily by energy_code_gap
Infrastructure: 0.426% avg pipe failure probability, 78% of ZIPs at high risk
73.9% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
→ Stable trendEPA violation counts by year across Washington County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 2 violations. Past 5 years: 4 total (4 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: $879
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
5,750 housing units in Washington 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 Washington County
Remediation costs are relatively manageable for most homeowners in Washington 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 Washington 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 Washington County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | OKAWVILLE | 1,521 | 12 |
| 2 | Nashville | 3,230 | 12 |
| 3 | Washington County Water Company | 11,374 | 12 |
| 4 | Millstone Pwd | 5,565 | 12 |
| 5 | Egyptian Water Company | 2,330 | 12 |
13 total water systems serve Washington County.
All ZIP Codes in Washington County
9 ZIP codes tracked in Washington County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 62803 | Hoyleton | 82 | B | 3 | $133K |
| 2 | 62877 | Richview | 81 | B | 2 | $116K |
| 3 | 62263 | Nashville | 76 | B | 12 (4 health) | $150K |
| 4 | 62876 | Radom | 72 | B | 0 | $77K |
| 5 | 62808 | Ashley | 70 | B | 1 | $141K |
| 6 | 62848 | Irvington | 70 | B | 1 | $90K |
| 7 | 62271 | Okawville | 63 | C | 0 | $167K |
| 8 | 62214 | Addieville | 53 | D | 0 | $175K |
| 9 | 62831 | Du Bois | 53 | D | 0 | $132K |
Recommended Buyer Guides for Washington County
Filtered against federal data, fitted to local risks.
- Best Lead Paint Test Kits — 73.9% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Washington County, Illinois
Overview
Washington County in Illinois covers 9 ZIP codes with an average Home Safety Score of C (69/100).
5 of 9 ZIP codes have recorded EPA violations. 4 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.