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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality scores for 60 cities in Illinois
It depends on your utility. 4 of the 56 Illinois water systems we grade from EPA records have a health-based violation in the last five years; the state averages 90/100 (2 above the national 88). Lowest graded: Calumet City (F). Highest: Champaign (A).
Illinois's official certified-lab list, when to test well vs city water, typical lab prices, and how to take a first-draw lead sample.
Across the 56 Illinois water systems we can grade from EPA records, the average score is 90/100 — 2 points above the U.S. national average of 88/100. 68% of graded Illinois cities (38 of 56) score above that national benchmark, and 36 earn a Grade A. 4 cities have at least one health-based EPA violation in the last five years. 4 cities are not graded because we have not yet matched them to an EPA water system.
The contaminants most commonly flagged in Illinois water systems are lead (aging infrastructure), atrazine (agricultural runoff) and nitrates (agricultural areas). See the full breakdown in our Illinois water quality rankings or compare against the cities with the best water quality in America.
See the top 20 cities with the cleanest, safest drinking water
Complete water quality rankings for every city in Illinois
150,000 residents
58,020 residents
50,179 residents
49,425 residents
39,725 residents
39,577 residents
37,983 residents
30,700 residents
30,193 residents
76,122 residents
53,970 residents
50,000 residents
37,470 residents
56,703 residents
43,212 residents
38,017 residents
75,750 residents
74,486 residents
70,875 residents
57,250 residents
54,583 residents
52,736 residents
44,500 residents
58,362 residents
42,000 residents
117,444 residents
47,856 residents
45,000 residents
41,000 residents
39,800 residents
77,610 residents
39,854 residents
87,149 residents
66,422 residents
39,018 residents
33,572 residents
44,476 residents
38,169 residents
2,721,308 residents
50,458 residents
156,406 residents
73,320 residents
60,675 residents
83,000 residents
33,103 residents
137,575 residents
40,661 residents
40,290 residents
16,813 residents
41,500 residents
31,620 residents
147,051 residents
183,000 residents
114,797 residents
160,000 residents
37,000 residents
75,201 residents
No EPA water-system match yet — no score.
42,214 residents
No EPA water-system match yet — no score.
41,097 residents
No EPA water-system match yet — no score.
30,479 residents
No EPA water-system match yet — no score.
Illinois water quality varies from Chicago's treated Lake Michigan water to rural communities relying on groundwater. The state's agricultural industry significantly impacts water quality in many regions, while older urban areas face infrastructure challenges. Illinois has been working to address both legacy contamination and emerging concerns.
Across the 56 Illinois cities graded from EPA records, the average water quality score is 90/100. 4 cities score below 70 (D or F) because of health-based violations, lead results, PFAS or historical readings near a limit. The highest-rated city is Champaign with a score of 100/100, while Calumet City has the most room for improvement at 55/100.
4 of the 56 Illinois cities we grade score below 70/100. If your city is one of them — or you just want extra protection — a certified filter is the fastest way to reduce exposure. The findings that drag a score down (lead, PFAS, arsenic, nitrate) are exactly the ones a basic carbon pitcher does not remove.
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Lake Michigan provides high-quality source water for Chicago and many suburban communities. The Illinois and Mississippi rivers serve other regions. Central and southern Illinois rely more heavily on groundwater and smaller surface water sources. Private wells serve many rural residents.
These contaminants have been detected in various Illinois water systems
Illinois EPA manages drinking water programs with standards generally aligned with federal requirements. The state has made significant investments in lead service line replacement, particularly in Chicago. Illinois has been addressing PFAS contamination and improving notification requirements.
Chicago and other older communities face significant lead service line concerns. Agricultural regions should monitor nitrate and pesticide levels. Some areas have naturally occurring radium in groundwater. Industrial areas may have specific contamination issues requiring attention.
Illinois residents in older homes should determine if they have lead service lines and consider certified lead removal filters. Rural residents should test private wells annually. Consider activated carbon filtration for agricultural chemical removal. Stay informed about your local water utility's infrastructure improvement plans.
Most Illinois cities we grade have tap water in good standing with EPA. With an average score of 90/100 across 56 graded cities, Illinois generally has good water quality. However, water quality varies by utility, so check your specific city's report.
The most common water quality concerns in Illinois include lead (aging infrastructure), atrazine (agricultural runoff), nitrates (agricultural areas). These contaminants can come from natural sources, industrial activities, or aging infrastructure. Review your city's specific report to see which contaminants affect your area.
Whether you need a water filter depends on your specific location and health concerns. With 4 Illinois cities grading D or F on EPA records, residents in those areas may benefit from filtration. Look for filters certified by NSF/ANSI to remove the specific contaminants found in your area.
Public water systems in Illinois are required to provide annual Consumer Confidence Reports (CCRs) to residents. You can usually find your report on your water utility's website, request it by phone, or access it through the EPA's database. Our city-level reports above summarize key information from these official sources.
Lead can be present in Illinois water, primarily from older plumbing infrastructure. Homes built before 1986 may have lead pipes or lead solder. While water treatment plants remove lead, it can leach into water from service lines and home plumbing. Check your city's specific report for lead testing data, and consider having your tap water tested if you live in an older home.
PFAS ("forever chemicals") have been detected in water systems across the United States, including in Illinois. These chemicals are associated with industrial sites, military bases, and firefighting foam use. The EPA has set new PFAS limits effective 2024. Check individual Illinois city reports for PFAS testing results in your area.
On EPA records, Champaign has the highest water quality score in Illinois at 100/100 (Grade A). However, "best" depends on your specific health concerns. View our Best Water Quality in Illinois page for a complete ranking.
Public water systems in Illinois are required by the EPA to test water regularly. Testing frequency depends on the contaminant: bacteria testing occurs daily to weekly, while chemical contaminants may be tested quarterly or annually. Results are published in annual Consumer Confidence Reports. Our site aggregates this data from EPA's SDWIS database.
Compare water quality across counties and find data for your area