Safest Drinking Water in Illinois 2026
Illinois has 5 public water systems serving 3,318,794 people. The safest system is Aurora in Aurora with a score of 100/100.
Top 5 Water Systems in Illinois
| # | Water System | City | Pop. Served | Source | Violations | Score |
|---|---|---|---|---|---|---|
| 1 | Aurora | Aurora | 183,000 | Surface water | 0 | A (100) |
| 2 | Il American-Champaign | Godfrey | 150,000 | Ground water | 0 | A (94) |
| 3 | Naperville | Naperville | 156,406 | Surface water | 0 | B (88) |
| 4 | Chicago | Chicago | 2,746,388 | Surface water | 0 | C (72) |
| 5 | Cicero | Cicero | 83,000 | Surface water | 1 | C (70) |
Water quality data for Illinois is sourced from the EPA Safe Drinking Water Information System (SDWIS), which tracks compliance for all public water systems.
Frequently Asked Questions
Aurora in Aurora has the highest Water Safety Score in Illinois at 100/100 (Grade A), serving 183,000 people.
Illinois has 5 public water systems serving 3,318,794 people. The average Water Safety Score is 85/100.
The Water Safety Score (0-100) is based on health violations (40%), contaminant exceedances (30%), enforcement history (20%), and monitoring violations (10%). Higher scores mean cleaner, safer water.
Water Safety Score: health violations (40%), contaminant exceedances (30%), enforcement history (20%), monitoring violations (10%).