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Illinois Water Quality
1,134
Utilities in database
12.0M
Residents served
5
With open violations
472
PFAS monitored
Quick Answer
Illinois public drinking water is served by 1,134 EPA-tracked water systems, providing service to approximately 12.0 million residents through public utilities. 5 of those systems currently have open health-based violations on record in the EPA federal database. 472 systems have official PFAS monitoring records from the EPA UCMR 5 program (2023–2025). About 20% of IL residents use private wells, which fall outside federal utility compliance monitoring.
5 Illinois water systems have open health-based violations recorded in EPA SDWIS. An open violation means a contaminant exceeded a federal limit and the violation has not been formally resolved in the federal database. Check individual utility pages for current status.
Open Health-Based Violations in Illinois
Records sourced from EPA SDWIS. A record may be under review or resolved at the utility level but not yet updated in federal records. Water Utility Report does not determine whether water is safe to drink.
Drinking Water in Illinois
Illinois has 1,134 community water systems serving approximately 12.0 million residents. Primary water sources include groundwater. The most commonly reported contaminants include lead, disinfection byproducts, nitrates. 20% of Illinois residents rely on private wells. IEPA holds primary enforcement authority under the Safe Drinking Water Act.
Highest Risk Utilities
Illinois systems with open health-based violations in EPA records.
Safest Large Utilities
Illinois systems with no open health violations serving 10,000+ residents.
Utilities in Illinois
301–325 of 1,134Illinois State University-normal
IL1135510 · 6,600 served
La Grange Highlands Sanitary District
IL0315860 · 6,600 served
Carlinville
IL1170150 · 6,598 served
Mahomet
IL0190450 · 6,580 served
Winthrop Harbor
IL0971950 · 6,565 served
Elburn
IL0890300 · 6,559 served
Geneseo
IL0730500 · 6,539 served
Northern Illinois University-dekalb
IL0375500 · 6,500 served
Carterville
IL1990150 · 6,484 served
Aqua Illinois-candlewick Dvn
IL0075050 · 6,426 served
Countryside
IL0310570 · 6,420 served
Dallas Rural Water District
IL0710010 · 6,370 served
Metropolis
IL1270150 · 6,309 served
Carmi
IL1930100 · 6,307 served
Fort Massac Pwd
IL1275050 · 6,290 served
Fairfield
IL1910100 · 6,202 served
Williamsville
IL1671300 · 6,198 served
Braidwood
IL1970150 · 6,194 served
Chillicothe
IL1430200 · 5,996 served
Beardstown
IL0170150 · 5,951 served
Peoria Heights
IL1434750 · 5,908 served
Mount Zion
IL1150350 · 5,833 served
Pinckneyville
IL1450150 · 5,804 served
Hoopeston
IL1830450 · 5,802 served
Pana
IL0210500 · 5,800 served
Key Contaminant Concerns in Illinois
These contaminants appear most frequently in Illinois utility records or pose elevated risk in this region based on EPA data.
Lead
Lead is a naturally occurring heavy metal that was widely used in plumbing infrastructure until it was banned for new installations in 1986. An estimated 9.2 million lead service lines still connect homes to public water mains across the United States, along with millions of homes with lead solder in their internal plumbing. Critically, a utility's water quality report can show zero detected lead at the treatment plant while your specific tap still delivers elevated lead — because the contamination happens inside the distribution system and your home's plumbing, not at the source.
EPA limit: 15 ppb (action level)
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always caused by human activity — nitrate is converted in the digestive system to nitrite, which then reacts with hemoglobin to form methemoglobin, a form of hemoglobin that cannot carry oxygen. In the body, nitrite also reacts with amines in food to form N-nitroso compounds (nitrosamines) — known carcinogens classified by the IARC as Group 2A (probable human carcinogens). The United States applies over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination in U.S. groundwater.
EPA limit: 10 mg/L
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
City Water Reports in Illinois
Tap water quality pages for Illinois cities — violations, PFAS records, utility profiles, and official source links.
Independent Water Testing
Find a certified lab in Illinois
Utility compliance records show what water systems report to the EPA. An independent test from a certified laboratory confirms what's actually in your tap water. Illinois labs can test for PFAS, lead, nitrates, bacteria, and dozens of other contaminants.
Explore Water Quality in Illinois
Illinois State University-normal
Violation history, PFAS records, and official source links
La Grange Highlands Sanitary District
Violation history, PFAS records, and official source links
Carlinville
Violation history, PFAS records, and official source links
PFAS monitoring records — Illinois
472 water systems in Illinois with EPA UCMR 5 records
Active drinking water violations
5 open health-based violations on record — view official EPA SDWIS data
Lead in Illinois drinking water
State-specific lead data, violation utilities, and testing guidance
PFAS in Illinois drinking water
State-specific PFAS data, MCL context, and treatment options
Certified water testing labs in Illinois
Labs certified for PFAS (EPA 533/537.1), lead, and bacteria testing
Water treatment options
Reverse osmosis, activated carbon, and filtration guides with cost ranges
Data sources and methodology
How WaterUtilityReport.com sources and validates official EPA data
Common Questions About Illinois Drinking Water
Does Illinois drinking water have PFAS?
472 Illinois water systems have EPA UCMR 5 PFAS monitoring records (2023–2025)
Which Illinois water utilities have open violations?
5 systems have open health-based violations in EPA SDWIS — search for your utility
How do I test my water in Illinois?
State-certified labs for PFAS (EPA 533/537.1), lead, nitrate, and bacteria testing
What treatment removes PFAS from IL tap water?
Reverse osmosis removes PFAS, lead, arsenic, and nitrates — cost, maintenance, and NSF certification explained
What do Illinois PFAS records tell me about my water?
EPA limits, health context, and what UCMR 5 detection above MRL means for your water
How is Illinois water quality data sourced here?
EPA SDWIS violations, UCMR 5 PFAS records, and CCR data — sources, accuracy notes, and limitations
Illinois Water FAQs
Data sources: Utility compliance and violation data from EPA SDWIS (Safe Drinking Water Information System). PFAS monitoring records from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule 5, 2023–2025). Contaminant data from EPA and ATSDR public references. This page summarizes public records — it is not a compliance determination. Methodology →
Last updated: 2026-04-17