Illinois tap water by county
Hardness, PFAS sampling, lead and violations for the largest water systems in 5 Illinois counties. In 3 of them, at least one large system detected PFAS in EPA testing (a detection isn't a violation).
| County | Largest system | Hardness | PFAS detected |
|---|---|---|---|
| Cook County | Chicago | Test (no data) | 0 of 6 systems |
| DuPage County | Naperville | Test (no data) | 2 of 6 systems |
| Lake County | Waukegan | 7.6 gpg (high) | 0 of 6 systems |
| Will County | Joliet | 17.1 gpg (low) | 1 of 6 systems |
| Kane County | Aurora | 18.2 gpg (low) | 3 of 6 systems |
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Hardness confidence: high = utility report; low = county estimate of untreated local water. Don't see your county? Use the water quality lookup.