Water Quality in Illinois
Water hardness and contaminant data for 11 cities across Illinois. Find your city below to see a detailed water quality profile.
11
Cities
219
Avg Hardness (PPM)
289
Hardest City (PPM)
Illinois Cities by Water Hardness
| City | Hardness (PPM) | Level | PFAS (ppt) | Source |
|---|---|---|---|---|
| Bloomington | 289 | Extremely Hard | 4 | Evergreen Lake, Lake Bloomington |
| Champaign | 285 | Extremely Hard | 5 | Mahomet Aquifer |
| Joliet | 279 | Extremely Hard | 4 | Des Plaines River wells, Lake Michigan p… |
| Peoria | 231 | Very Hard | 5 | Illinois River |
| Springfield | 227 | Very Hard | 5 | Lake Springfield |
| Naperville | 220 | Very Hard | 5 | Deep groundwater wells |
| Elgin | 191 | Very Hard | 5 | Fox River wells, Lake Michigan blend |
| Decatur | 191 | Very Hard | 4 | Lake Decatur |
| Rockford | 185 | Very Hard | 4 | Groundwater wells |
| Schaumburg | 175 | Hard | 4 | Lake Michigan via NW Water Commission |
| Chicago | 140 | Hard | 6 | Lake Michigan |