Illinois
Water quality data from the EPA Safe Drinking Water Information System
Water Systems
26,675
Active public water systems
Population Served
12.59M
Residents with piped water
Lead Violations
91
Systems exceeding 15 ppb
Copper Violations
465
Lead & Copper Rule
Average Lead Level
EPA Action Level: 15 ppb
MCLG (health goal): 0 ppb
Average across 2773 systems with reported lead data.
Violations Detected
556 water systems in Illinois have reported violations under the Lead and Copper Rule. These utilities are required to notify customers and take corrective action.
Water Systems: Highest Lead Levels
| System Name | City | Population | Lead Level | Status | Sample Date |
|---|---|---|---|---|---|
| ELGIN | 114,797 | 51.10 ppb | Violation | 2025-12-31 | |
| LOCKPORT | 23,100 | 33.00 ppb | Violation | 2025-12-31 | |
| GODFREY | 137,575 | 25.00 ppb | Violation | 2025-12-31 | |
| BARTLETT | 41,500 | 24.60 ppb | Violation | 2025-12-31 | |
| LIBERTYVILLE | 20,500 | 24.50 ppb | Violation | 2025-12-31 | |
| LEMONT | 17,500 | 24.00 ppb | Violation | 2025-06-30 | |
| AURORA | 183,000 | 20.60 ppb | Violation | 2025-06-30 | |
| NORTH AURORA | 18,350 | 18.00 ppb | Violation | 2025-06-30 | |
| MORTON GROVE | 25,297 | 17.20 ppb | Violation | 2025-12-31 | |
| NORTHBROOK | 34,407 | 16.00 ppb | Violation | 2025-06-30 | |
| HOMEWOOD | 19,463 | 16.00 ppb | Violation | 2025-12-31 | |
| HERRIN | 12,747 | 16.00 ppb | Violation | 2025-12-31 | |
| CALUMET CITY | 37,000 | 15.40 ppb | Violation | 2025-12-31 | |
| PALATINE | 70,875 | 15.00 ppb | OK | 2025-12-31 | |
| EAST MOLINE | 21,374 | 15.00 ppb | OK | 2025-06-30 |
Showing top 15 of 2619 systems with lead data. Action level: 15 ppb.
Systems With Active Violations
These water systems have exceeded EPA limits and must take corrective action.
AURORA · Pop. 183,000
Lead: 20.60 ppb (2025-06-30)
ROCKFORD · Pop. 147,051
Lead: 14.00 ppb (2025-06-30)
GODFREY · Pop. 137,575
Lead: 25.00 ppb (2025-12-31)
ELGIN · Pop. 114,797
Lead: 51.10 ppb (2025-12-31)
KANKAKEE · Pop. 80,000
Lead: 2.40 ppb (2025-12-31)
DEKALB · Pop. 45,000
Lead: 11.00 ppb (2025-06-30)
BARTLETT · Pop. 41,500
Lead: 24.60 ppb (2025-12-31)
CARPENTERSVILLE · Pop. 37,983
Lead: 1.60 ppb (2025-12-31)
CALUMET CITY · Pop. 37,000
Lead: 15.40 ppb (2025-12-31)
NORTHBROOK · Pop. 34,407
Lead: 16.00 ppb (2025-06-30)
GALESBURG · Pop. 31,620
Lead: 0.00 ppb (2025-12-31)
ALGONQUIN · Pop. 30,700
Lead: 0.00 ppb (2025-12-31)
Water Source Types
Air Quality
GoodAvg AQI
45
PM2.5
6.2 µg/m³
Unhealthy Days
5
Primary Pollutant
Ozone
Source: EPA AirNow & American Lung Association 2024 State of the Air. AQI scale: 0–50 Good · 51–100 Moderate · 101–150 Sensitive Groups · 151+ Unhealthy.
PFAS Contamination
Moderate DetectionPFAS (per- and polyfluoroalkyl substances), known as “forever chemicals,” are a group of synthetic chemicals that persist indefinitely in the environment and human body. The EPA set a maximum contaminant level (MCL) of 4 parts per trillion (ppt) for PFOA and PFOS in April 2024. View national PFAS tracker →
Systems Tested
412
PFAS Detected
148
Detection Rate
35.9%
Exceeding MCL (4 ppt)
32(7.8%)
Highest recorded level: 62 ppt (EPA MCL: 4 ppt). Large industrial state; Chicago metro area systems affected; large systems flagged by USGS