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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
451–475 of 1,134Abingdon
IL0950050 · 3,275 served
Casey
IL0230050 · 3,274 served
Virden
IL1171100 · 3,274 served
Mount Sterling
IL0090100 · 3,271 served
Indian Head Park
IL0311410 · 3,240 served
Nashville
IL1890300 · 3,230 served
North East Marion County Water Cmpny
IL1210030 · 3,220 served
Knoxville
IL0950300 · 3,120 served
East Dundee
IL0890250 · 3,115 served
Smg Water Coop
IL1370030 · 3,110 served
Sleepy Hollow
IL0890750 · 3,100 served
Momence
IL0910650 · 3,075 served
Christopher
IL0550150 · 3,072 served
Aqua Illinois-hawthorn Woods
IL0975040 · 3,065 served
Lakeside Pwd
IL0775150 · 3,065 served
Savanna
IL0150250 · 3,020 served
Winnebago
IL2010500 · 3,000 served
Oasis Mhp
IL0315185 · 3,000 served
Newton
IL0790100 · 2,977 served
Marquette Heights
IL1790400 · 2,974 served
Dixmoor
IL0310660 · 2,973 served
Bushnell
IL1090150 · 2,972 served
Havana
IL1250200 · 2,963 served
Menard Correctional Center
IL1575550 · 2,950 served
Pittsburg
IL1990600 · 2,948 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
Abingdon
Violation history, PFAS records, and official source links
Casey
Violation history, PFAS records, and official source links
Virden
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