City Water Quality Rankings in Illinois
635 cities ranked by drinking water quality.
Popular city water quality comparisons
Trending Cities
#529
Virginia
County, IL
48 D
#530 Grayville
County, IL
47 D
#531 Marion
County, IL
47 D
#532 Algonquin
County, IL
46 D
#533 Dwight
County, IL
46 D
#534 Gorham
County, IL
46 D
#535 Norridge
County, IL
46 D
#536 Ottawa
County, IL
46 D
#537 Rochelle
County, IL
46 D
#538 Clinton
County, IL
45 D
#539 Collinsville
County, IL
45 D
#540 Manteno
County, IL
45 D
#541 Mt. Morris
County, IL
45 D
#542 Plano
County, IL
45 D
#543 Chicago
County, IL
44 F
#544 Enfield
County, IL
44 F
#545 Fairfield
County, IL
44 F
#546 Montgomery
County, IL
44 F
#547 Mounds
County, IL
44 F
#548 Elmwood Park
County, IL
43 F
#549 Prospect Heights
County, IL
43 F
#550 St. Jacob
County, IL
43 F
#551 Kincaid
County, IL
42 F
#552 Mount Prospect
County, IL
42 F
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.