City Water Quality Rankings in Illinois
631 cities ranked by drinking water quality.
Popular city water quality comparisons
Trending Cities
#433
Buffalo Grove
County, IL
58 D
#434 Cobden
County, IL
58 D
#435 Hardwood Heights
County, IL
58 D
#436 Lake Forest
County, IL
58 D
#437 Mokena
County, IL
58 D
#438 Morton Grove
County, IL
58 D
#439 Onarga
County, IL
58 D
#440 Peru
County, IL
58 D
#441 Red Bud
County, IL
58 D
#442 Rock Falls
County, IL
58 D
#443 Summit
County, IL
58 D
#444 Tinley Park
County, IL
58 D
#445 Zeigler
County, IL
58 D
#446 Alton
County, IL
57 D
#447 Beardstown
County, IL
57 D
#448 Georgetown
County, IL
57 D
#449 Lake In The Hills
County, IL
57 D
#450 Moweaqua
County, IL
57 D
#451 Warrensburg
County, IL
57 D
#452 Bartlett
County, IL
56 D
#453 Bushnell
County, IL
56 D
#454 Elburn
County, IL
56 D
#455 Harvard
County, IL
56 D
#456 Morris
County, IL
56 D
Frequently Asked Questions
How are city water quality rankings calculated in Illinois?
WaterQ city rankings are based on EPA SDWIS data across local public water systems, including contaminant detections, compliance violations, and recency-weighted score signals.
Can I compare two cities in Illinois?
Yes. Use the city comparison links on this page or open the Compare tool to evaluate two cities side by side on score, grade, and water system coverage.
How often does WaterQ refresh city data?
City-level metrics refresh when new EPA data is processed. Check city pages for latest score and violation context.