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
426–450 of 1,134Fountain Water District
IL1330020 · 3,650 served
Fairbury
IL1050350 · 3,633 served
Riverwoods
IL0971450 · 3,618 served
Il American-tolono
IL0191000 · 3,604 served
Woodlawn
IL0810450 · 3,587 served
Three County Pwd
IL1195450 · 3,575 served
Hainesville
IL0970400 · 3,528 served
Western Wayne Water District
IL1910010 · 3,516 served
Johnston City
IL1990500 · 3,509 served
South Jacksonville
IL1370400 · 3,508 served
Gibson City
IL0530100 · 3,500 served
Le Roy
IL1130750 · 3,498 served
Forsyth
IL1150200 · 3,490 served
Tritownship Water District
IL1190080 · 3,470 served
Aledo
IL1310050 · 3,470 served
Oregon
IL1410400 · 3,449 served
Hardinville Water Company
IL0330020 · 3,403 served
Mackinaw
IL1790350 · 3,399 served
Rushville
IL1690200 · 3,375 served
Carlyle
IL0270300 · 3,373 served
Lake Sara Area Water Co-op, Inc.
IL0495150 · 3,352 served
Fulton
IL1950250 · 3,346 served
Pontoon Beach Pwd
IL1195300 · 3,325 served
Galena
IL0850200 · 3,308 served
Il American-liberty Ridge West
IL0435650 · 3,307 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