Tap Water Results

Illinois tap water quality

1,788 community water systems serving 12.1 million people.

Data: U.S. EPA · How we read the data · How we check it

13
systems with PFAS above a federal limit
353,817
people served by them
479
systems EPA tested for PFAS
18
systems above the lead action level

PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 9 more systems have no recent lead results in EPA's database.

Water systems with PFAS above the federal limit

Based on EPA's UCMR 5 results (2023–2025) compared to the April 2024 limits, the way EPA compares them. Systems have until 2029 to comply. Largest first.

Illinois PFAS report: chart, rankings and data to download →

Illinois's own PFAS limits

Illinois enforces its own drinking water limits for PFAS (effective: 2029-04-26 (compliance), rule published Ill. Reg. 2026-02-27): PFOA 4 ppt, PFOS 4 ppt, PFHxS 10 ppt, PFNA 10 ppt, HFPO-DA 10 ppt. The federal limits are 4 ppt for PFOA and PFOS.

35 Ill. Adm. Code 611 identical-in-substance rule plus Hazard Index MCL. Public Act 104-0510 (June 2026) keeps them if EPA rescinds federal limits.

Source: Illinois EPA: PFAS, checked 2026-11-14. Utility pages compare each system's EPA results with these limits. State compliance is judged on the state's own sampling.

Largest water systems in Illinois

Illinois cities and towns

Most health-based violations since 2016

All Illinois utilities on this site

Every Illinois system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 1,788 systems as CSV.

Questions

Does Illinois tap water have PFAS?

EPA tested 479 community water systems in Illinois for 29 PFAS between 2023 and 2025. 38 had at least one regulated PFAS detected, and 13 had an entry-point average above a 2024 federal limit. Those 13 systems serve about 353,817 people (3% of people on community water in Illinois). Systems have until 2029 to meet the limits.

How many Illinois water systems have violations?

431 systems in Illinois had at least one health-based violation since 2016 (1,091 violations in total). 1,014 violations are currently listed as unaddressed.

Which Illinois water systems are over the lead action level?

18 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 9 systems have no lead results in EPA's database from the last five years, including 1 whose last result was above the action level. Lead depends on each home's pipes, so a test of your own tap is the only way to know your level.

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.