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
851–875 of 1,134Apple Creek Water Coop
IL1370040 · 968 served
Ashton
IL1030100 · 967 served
Ramsey
IL0510200 · 966 served
Wataga
IL0950600 · 965 served
Rapids City
IL1610600 · 962 served
Percy
IL1570350 · 961 served
Clay City
IL0250050 · 957 served
Atkinson
IL0730200 · 955 served
Mendon
IL0010500 · 953 served
Leland
IL0990350 · 951 served
Harbor Point Estates Mhp
IL0317010 · 950 served
Liberty Park Homeowners Association
IL0435600 · 950 served
Stronghurst
IL0710400 · 950 served
Boyleston Waterworks Corp
IL1915050 · 948 served
Kinmundy
IL1210300 · 940 served
Mansfield
IL1470300 · 939 served
Goodfield
IL2034450 · 936 served
Stonington
IL0210550 · 932 served
Prairie Path Water Company-apple Canyon
IL0855150 · 931 served
Sumner
IL1010300 · 921 served
Willow Lake Estates Mhp
IL0894400 · 920 served
Birds Pinkstaff Water District
IL1015300 · 920 served
Avon
IL0570100 · 920 served
Aqua Illinois-moecherville
IL0895300 · 920 served
Roseville
IL1870200 · 915 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