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
276–300 of 1,134Princeton
IL0110850 · 7,832 served
Rock Island Arsenal, Us Army
IL1615387 · 7,800 served
Hampshire
IL0890450 · 7,758 served
Rockton
IL2010350 · 7,685 served
Vandalia
IL0510350 · 7,616 served
Marengo
IL1110650 · 7,572 served
Silvis
IL1610700 · 7,473 served
Clinton
IL0390050 · 7,200 served
Duquoin
IL1450100 · 7,169 served
Sandwich
IL0374850 · 7,156 served
Raccoon Water Company
IL1215100 · 7,080 served
North Riverside
IL0312160 · 7,071 served
Mount Carmel
IL1850200 · 7,015 served
Aqua Illinois-university Park
IL1975030 · 7,002 served
Southeast Regional Water Facility
IL0430060 · 6,940 served
Mendota
IL0990550 · 6,926 served
Stickney
IL0313000 · 6,902 served
Abs Water Coop
IL0015350 · 6,858 served
American Water Oper and Maintenance, Llc
IL1635237 · 6,779 served
Il American-valley View
IL0437350 · 6,721 served
Curran-gardner Township Pwd
IL1675350 · 6,651 served
Litchfield
IL1350400 · 6,648 served
Bond/madison Water Company
IL0050020 · 6,645 served
Volo
IL0971770 · 6,629 served
Il American-dupage Utility
IL0430552 · 6,613 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