McHenry County, Illinois
21 ZIP codes · Avg score 68/100 · Grade C · Updated 2026-06-03
Monitoring figures for McHenry County indicate average water quality overall — some ZIP codes among the 21 tracked have recorded health-based violations, while others operate cleanly, making individual ZIP-level data the most actionable reference point.
How McHenry County Compares
How McHenry County Compares
McHenry County scores 7 points above the Illinois state average (61/100) and 0 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: McHenry County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 11.7 (asthma 9.6%, diabetes 10.5%)
Estimated additional annual cost per homeowner: $1,795, driven primarily by flood
Infrastructure: 0.343% avg pipe failure probability, 20% of ZIPs at high risk
48.5% of homes built before 1978 (lead paint era)
Violation History (2023–2025)
→ Stable trendEPA violation counts by year across McHenry County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 10 violations. Past 5 years: 20 total (20 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: $1,795
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
131,039 housing units in McHenry 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 McHenry County
Remediation costs are relatively manageable for most homeowners in McHenry 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 McHenry 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 McHenry County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Mchenry | 22,335 | 30 |
| 2 | Woodstock | 25,630 | 19 |
| 3 | Prairie Path Water Company-killarney | 1,232 | 19 |
| 4 | Wonder Lake (niu) | 1,950 | 19 |
| 5 | CRYSTAL LAKE | 40,661 | 18 |
31 total water systems serve McHenry County.
All ZIP Codes in McHenry County
21 ZIP codes tracked in McHenry County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 60097 | Wonder Lake | 82 | B | 9 (1 health) | $216K |
| 2 | 60142 | Huntley | 79 | B | 1 (1 health) | $324K |
| 3 | 60033 | Harvard | 78 | B | 0 | $199K |
| 4 | 60152 | Marengo | 78 | B | 0 | $259K |
| 5 | 60098 | Woodstock | 77 | B | 3 (1 health) | $258K |
| 6 | 60156 | Lake In The Hills | 76 | B | 1 | $296K |
| 7 | 60042 | Island Lake | 75 | B | 0 | $244K |
| 8 | 60102 | Algonquin | 73 | B | 0 | $321K |
| 9 | 60180 | Union | 72 | B | 2 | $290K |
| 10 | 60013 | Cary | 71 | B | 1 | $291K |
| 11 | 60034 | Hebron | 70 | B | 2 | $254K |
| 12 | 60021 | Fox River Grove | 69 | C | 4 | $286K |
| 13 | 60050 | Mchenry | 66 | C | 7 (1 health) | $245K |
| 14 | 60072 | Ringwood | 63 | C | 0 | $390K |
| 15 | 60051 | Mchenry | 61 | C | 7 (1 health) | $268K |
| 16 | 60012 | Crystal Lake | 58 | C | 2 | $397K |
| 17 | 60039 | Crystal Lake | 58 | C | 2 | — |
| 18 | 60071 | Richmond | 58 | C | 0 | $290K |
| 19 | 60014 | Crystal Lake | 54 | D | 2 | $296K |
| 20 | 60001 | Alden | 53 | D | 0 | — |
| 21 | 60081 | Spring Grove | 50 | D | 0 | $333K |
Recommended Buyer Guides for McHenry County
Retailer arrangements don't shape what appears here — the selection logic is independent, filtered against EPA detections and the federal hazard data on file for this county.
- Best Water Filters for Lead — Lead above EPA action level in 1 ZIP code
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- 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 McHenry County, Illinois
Overview
McHenry County in Illinois covers 21 ZIP codes with an average Home Safety Score of C (68/100).
13 of 21 ZIP codes have recorded EPA violations. 5 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.