Water quality · IL

Illinois Water Quality (2026)

Lake Michigan supplies most of northern Illinois with soft–moderate water; lead service lines remain a concern in older Chicago-area homes.

Our Illinois coverage focuses on the 1 metros below: Chicago. Each city page lists the utility's water source, hardness in grains per gallon, any contaminants flagged above EWG's stricter health guideline, and the whole-house system type that matches that specific profile, not a generic recommendation copied across the state.

If your Illinois city is not in the list yet, the nearest covered metro is usually a reasonable proxy: regional source water and treatment plants are typically shared across nearby municipalities. Private wells in Illinois are a different story and need a mail-in lab panel, the utility CCR will not apply.

Sources: EWG; city data