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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
476–500 of 1,134Fmc Water Company
IL1210020 · 2,945 served
Arcola
IL0410050 · 2,927 served
Mount Morris
IL1410350 · 2,861 served
Heyworth
IL1130650 · 2,853 served
Mission Brook Sd
IL0315920 · 2,852 served
Holiday Shores Sd
IL1195110 · 2,840 served
Albion
IL0470050 · 2,839 served
Southern Il University-edwardsville
IL1195550 · 2,817 served
El Paso
IL2030150 · 2,812 served
Mcleansboro
IL0650200 · 2,812 served
South Palos Twsp Sanitary Dist
IL0310140 · 2,800 served
North Morgan Water Coop
IL1375050 · 2,763 served
Hamilton
IL0670400 · 2,753 served
Trenton
IL0270500 · 2,742 served
Pawnee
IL1670850 · 2,739 served
Lakemoor
IL0970270 · 2,720 served
Burnside Pwd
IL0875050 · 2,702 served
Lena
IL1770300 · 2,680 served
Colona West
IL0730550 · 2,640 served
Fox Lake Hills Subdivision - Lake Co Pw
IL0975550 · 2,628 served
Round Lake Heights
IL0970260 · 2,622 served
Moultrie County Rwd
IL1395150 · 2,600 served
Bridgeport
IL1010100 · 2,572 served
Saddlebrook Farms
IL0970120 · 2,558 served
Mason City
IL1250350 · 2,558 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
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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