State Hub
Illinois Water Quality
1,134
Utilities in database
12.0M
Residents served
20%
On private wells
3
Key contaminants tracked
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.
Utilities in Illinois
576–600 of 1,134Mitchellsville Pwd
IL1655200 · 1,970 served
Merrionette Park
IL0311890 · 1,969 served
Steeleville
IL1570650 · 1,960 served
Sterling Estates Mhp
IL0315850 · 1,954 served
Wonder Lake (niu)
IL1115850 · 1,950 served
Il American-waycinden
IL0317550 · 1,934 served
Glen Ellyn Heights Subdivision
IL0435500 · 1,931 served
Steeple Run Sbdv
IL0437160 · 1,931 served
Lexington
IL1130800 · 1,930 served
Belle Rive
IL0810050 · 1,930 served
Minonk
IL2030400 · 1,928 served
Marissa
IL1630750 · 1,921 served
De Soto
IL0770200 · 1,910 served
Waltonville
IL0810400 · 1,901 served
Princeville
IL1430750 · 1,901 served
South Roxana
IL1190970 · 1,891 served
Aqua Illinois-oak Run
IL0955200 · 1,885 served
Girard
IL1170450 · 1,885 served
Central Macoupin County Rwd
IL1170040 · 1,883 served
Bluford
IL0810100 · 1,880 served
Lacon
IL1230100 · 1,878 served
Rural Wabash County Water District
IL1850010 · 1,877 served
Poplar Grove South
IL0070300 · 1,877 served
Hampton
IL1610300 · 1,863 served
Prairie Dupont Pwd
IL1635070 · 1,863 served
Key Contaminant Concerns in Illinois
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.
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always from human activity — nitrate interferes with the blood's ability to carry oxygen. The United States produces over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination.
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.
Illinois Water FAQs
Quick Links
Data source: Utility data from EPA SDWIS. 1,134 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-17