The Illinois Water Hardness data presented in this chart has all been verified by Aquatell directly from primary sources. Typically, this means we found the data on municipal water reports or we emailed or talked with municipal officials from the public utilities department.
If the water hardness data from your city is missing from this list please contact us and let us know. We can typically track down the info and add it to our chart in about a week.
If you're looking to reduce your water hardness level, have a look at a professional-grade water softener. Here are the water hardness values for the cities and towns in Illinois:
| City | AVG Hardness PPM / mg/L | AVG Hardness Grains per Gallon |
|---|---|---|
| Arlington Heights | 134 | 7.9 |
| Aurora | 130 | 7.7 |
| Aurora | 130 | 7.7 |
| Bolingbrook | 108 | 6.4 |
| Capital | 115 | 6.8 |
| Carol Stream | 418 | 24 |
| Champaign | 90 | 5.3 |
| Chicago | 148 | 8 |
| Chicagoland | 148 | 8.7 |
| Cicero | 187 | 11 |
| Columbus | 120 | 7 |
| Crystal Lake | 137 | 8 |
| Danville | 191 | 11 |
| Decatur | 194 | 11 |
| Dekalb | 188 | 11 |
| Des Plaines | 350 | 18 |
| Downers Grove | 288 | 17 |
| East Peoria | 250 | 15 |
| East Saint Louis | 210 | 12 |
| Elgin | 128 | 7.5 |
| Elgin | 128 | 7.5 |
| Elmhurst | 362 | 21 |
| Elmwood Park | 218 | 13 |
| Evanston | 134 | 7.9 |
| Glen Ellyn | 148 | 8.7 |
| Glenview | 150 | 8.8 |
| Granite City | 250 | 15 |
| Joliet | 388 | 23 |
| Kankakee | 196 | 11 |
| Lombard | 344 | 20 |
| Melrose Park | 222 | 12 |
| Moline | 210 | 12 |
| Mount Prospect | 110 | 6.5 |
| Naperville | 288 | 17 |
| New Trier | 150 | 8.8 |
| Oak Lawn | 222 | 13 |
| Oak Park | 212 | 12 |
| Orland Park | 322 | 19 |
| Palatine | 245 | 14 |
| Peoria | 450 | 26.4 |
| Plainfield | 280 | 16 |
| Rockford | 22 | 1.3 |
| Rockford | 22 | 1.3 |
| Romeoville | 395 | 24 |
| Skokie | 134 | 7.9 |
| Springfield | 115 | 6.8 |
| Thornton | 196 | 11.5 |
| Waukegan | 140 | 8.2 |
| Wayne | 333.8 | 19.6 |
| Wheeling | 134 | 7.9 |
