Illinois tap water
13 of 477 Illinois water systems with full PFAS testing (3%) averaged above a 2024 federal PFAS level at one or more sampling points.
- 1,784 active community water systems in the EPA file; 436 serve 3,300+ people and have a full PFAS set.
- 322 systems had at least one health-based violation since 2021-10-26.
- 18 systems report a lead 90th percentile above 15 ppb (some results are old; check each system page).
Largest systems
| System | People served | PFAS above a 2024 level? | Health-based violations since 2021-10-26 |
|---|---|---|---|
| Chicago | 2,721,308 | No | 0 |
| Aurora | 183,000 | No | 0 |
| Joliet | 160,000 | No | 1 |
| Naperville | 156,406 | No | 0 |
| IL American-Champaign | 150,000 | No | 0 |
| Rockford | 147,051 | No | 0 |
| IL American-Peoria | 137,575 | Yes, at one or more sampling points | 0 |
| IL American-East St Louis | 131,368 | No | 0 |
Counties
Cook County106 systems with full PFAS testingLake County35 systems with full PFAS testingDuPage County30 systems with full PFAS testingWill County21 systems with full PFAS testingKane County17 systems with full PFAS testingMadison County16 systems with full PFAS testingMcHenry County12 systems with full PFAS testing
All 41 utilities with a page in Illinois
- Aqua Illinois-Kankakee 80,000
- Arlington Heights 73,320
- Aurora 183,000
- Bartlett 41,500
- Bloomington 79,000
- Buffalo Grove 43,212
- Chicago 2,721,308
- Cicero 83,000
- Decatur 76,122
- Des Plaines 60,675
- Downers Grove 49,425
- Elgin 114,797
- Elmhurst 45,000
- Evanston 74,486
- Glenview 47,856
- Hoffman Estates 50,179
- IL American-Alton 46,127
- IL American-Champaign 150,000
- IL American-East St Louis 131,368
- IL American-Peoria 137,575
- IL American-West Suburban 73,978
- Joliet 160,000
- Lombard 44,476
- Moline 44,500
- Naperville 156,406
- Normal 52,736
- O Fallon 46,603
- Oak Lawn 58,362
- Oak Park 54,583
- Orland Park 58,020
- Palatine 70,875
- Plainfield 50,000
- Quincy 42,000
- Rockford 147,051
- Romeoville 50,458
- Schaumburg 75,750
- Skokie 66,422
- Springfield 117,444
- Tinley Park 56,703
- Waukegan 87,149
- Wheaton 53,970
Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.