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
1,076–1,100 of 1,134Valley View Estates
IL1631150 · 580 served
Thomson
IL0150350 · 580 served
Hopkins Park
IL0910040 · 579 served
Sawyerville
IL1170850 · 578 served
Williamsfield
IL0950650 · 575 served
College View Subdivision
IL1975400 · 570 served
Blandinsville
IL1090100 · 569 served
Lake View Mhp
IL0975345 · 568 served
Godley Public Water District
IL1970130 · 566 served
Elkhart
IL1070150 · 565 served
Dhs Rushville Treatment and Detention
IL1690020 · 565 served
Andover
IL0730100 · 565 served
Ashley
IL1890100 · 565 served
Schram City
IL1350600 · 563 served
Cullom
IL1050200 · 563 served
Southwestern Il Correctional Center
IL1630030 · 563 served
Dorchester
IL1170250 · 562 served
Carlock
IL1130250 · 562 served
Grand Tower
IL0770400 · 559 served
Sidell
IL1830850 · 557 served
Mark
IL1550250 · 555 served
Augusta
IL0670050 · 553 served
Danforth
IL0750350 · 550 served
Mulberry Grove
IL0050100 · 548 served
Burt Estates Mhc
IL0630070 · 543 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