DeKalb County, Illinois
12 ZIP codes · Avg score 57/100 · Grade C · Updated 2026-06-03
For most households in DeKalb County, the 12 tracked ZIP codes show adequate but uneven water quality.
How DeKalb County Compares
How DeKalb County Compares
DeKalb 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: DeKalb County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 11.8 (asthma 10.4%, diabetes 10.3%)
Estimated additional annual cost per homeowner: $1,868, driven primarily by flood
Infrastructure: 0.407% avg pipe failure probability, 58% of ZIPs at high risk
61.3% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
→ Stable trendEPA violation counts by year across DeKalb County water systems. Health-based shown in red, total in blue.
Peak year: 2024 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: $1,868
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
41,737 housing units in DeKalb 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 DeKalb County
Remediation costs are relatively manageable for most homeowners in DeKalb 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 DeKalb 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 DeKalb County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | MALTA | 1,143 | 92 |
| 2 | Cortland Corners Mhp | 250 | 92 |
| 3 | Sycamore | 18,500 | 18 |
| 4 | Genoa | 5,298 | 14 |
| 5 | Cortland | 4,270 | 9 |
22 total water systems serve DeKalb County.
All ZIP Codes in DeKalb County
12 ZIP codes tracked in DeKalb County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 60112 | Cortland | 70 | B | 1 | $202K |
| 2 | 60548 | Sandwich | 69 | C | 6 (1 health) | $240K |
| 3 | 60145 | Kingston | 65 | C | 9 (2 health) | $252K |
| 4 | 60550 | Shabbona | 65 | C | 2 | $193K |
| 5 | 60178 | Sycamore | 58 | C | 4 | $263K |
| 6 | 60146 | Kirkland | 57 | C | 0 | $209K |
| 7 | 60520 | Hinckley | 57 | C | 0 | $293K |
| 8 | 60135 | Genoa | 56 | C | 1 | $238K |
| 9 | 60556 | Waterman | 54 | D | 1 | $243K |
| 10 | 60150 | Malta | 50 | D | 92 (1 health) | $184K |
| 11 | 60115 | Dekalb | 42 | D | 4 | $206K |
| 12 | 60111 | Clare | 40 | D | 0 | $374K |
Recommended Buyer Guides for DeKalb County
Below: editorial picks, no sponsored placements.
- Best Lead Paint Test Kits — 61.3% 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 DeKalb County, Illinois
Overview
DeKalb County in Illinois covers 12 ZIP codes with an average Home Safety Score of C (57/100).
9 of 12 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.