LaSalle County, Illinois
24 ZIP codes · Avg score 67/100 · Grade C · Updated 2026-06-03
Spanning 24 ZIP codes, LaSalle County lands near the national median for water safety — compliance results are mixed, and the county's middle-grade standing reflects genuine variability rather than a single systemic problem.
How LaSalle County Compares
How LaSalle County Compares
LaSalle County scores 6 points above the Illinois state average (61/100) and 1 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: LaSalle County, Illinois
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.8 (asthma 10.3%, diabetes 12.4%)
Estimated additional annual cost per homeowner: $1,842, driven primarily by flood
Infrastructure: 0.455% avg pipe failure probability, 71% of ZIPs at high risk
74% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
↓ Improving trendEPA violation counts by year across LaSalle County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 15 violations. Past 5 years: 36 total (36 health-based). Health-based violations are declining versus the prior 2-year window.
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: $1,842
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
41,327 housing units in LaSalle 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 LaSalle County
Remediation costs are relatively manageable for most homeowners in LaSalle 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 LaSalle 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 LaSalle County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | OTTAWA | 18,097 | 87 |
| 2 | Naplate | 465 | 73 |
| 3 | Fields Hill Improvement Association | 312 | 73 |
| 4 | Retz Addn Improvement Association | 168 | 73 |
| 5 | La Salle County Nursing Home | 100 | 73 |
36 total water systems serve LaSalle County.
All ZIP Codes in LaSalle County
24 ZIP codes tracked in LaSalle County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 60552 | Somonauk | 87 | A | 0 | $245K |
| 2 | 61370 | Tonica | 87 | A | 0 | $153K |
| 3 | 61332 | Leonore | 85 | A | 0 | $83K |
| 4 | 60531 | Leland | 84 | B | 3 | $226K |
| 5 | 61325 | Grand Ridge | 83 | B | 4 | $180K |
| 6 | 61334 | Lostant | 83 | B | 4 (1 health) | $120K |
| 7 | 61360 | Seneca | 82 | B | 0 | $241K |
| 8 | 61358 | Rutland | 79 | B | 0 | $204K |
| 9 | 61348 | Oglesby | 77 | B | 6 | $139K |
| 10 | 61377 | Wenona | 68 | C | 7 (1 health) | $127K |
| 11 | 61350 | Ottawa | 66 | C | 73 (3 health) | $157K |
| 12 | 61301 | La Salle | 65 | C | 6 (3 health) | $118K |
| 13 | 60551 | Sheridan | 64 | C | 3 | $247K |
| 14 | 60549 | Serena | 60 | C | 0 | $292K |
| 15 | 60557 | Wedron | 60 | C | 0 | — |
| 16 | 60518 | Earlville | 58 | C | 0 | $151K |
| 17 | 61354 | Peru | 57 | C | 29 (5 health) | $160K |
| 18 | 61342 | Mendota | 56 | C | 7 (1 health) | $133K |
| 19 | 61341 | Marseilles | 53 | D | 11 (1 health) | $179K |
| 20 | 61373 | Utica | 51 | D | 7 (1 health) | $223K |
| 21 | 61316 | Cedar Point | 50 | D | 0 | $87K |
| 22 | 61321 | Dana | 50 | D | 0 | $87K |
| 23 | 61371 | Triumph | 50 | D | 0 | — |
| 24 | 61372 | Troy Grove | 50 | D | 0 | $186K |
Recommended Buyer Guides for LaSalle County
Eight risk categories drive the selection — PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback — and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.
- Best Water Filters for Lead — Lead above EPA action level in 3 ZIP codes
- Best Lead Paint Test Kits — 74% 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
Deep Dive Reports
Detailed analysis for LaSalle County, Illinois
Overview
LaSalle County in Illinois covers 24 ZIP codes with an average Home Safety Score of C (67/100).
12 of 24 ZIP codes have recorded EPA violations. 16 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.