487 public water systems in Illinois were sampled in EPA's UCMR 5 programme (2023–2025); we show six PFAS and lithium. Read 2026-10-31.
29 of 487 systems had at least one sample above a 2024 federal limit; 153 had at least one PFAS found above the reporting level; 334 had none found above the reporting level.
A single sample above a 2024 limit is a measurement, not a violation. Compliance is judged on running yearly averages, and water systems have until 2029 to meet the limits. On 20 May 2026 EPA proposed giving qualifying systems until 2031 for PFOA and PFOS and removing the limits for PFHxS, PFNA and HFPO-DA; those proposals were not final when we last checked (5 Nov 2026). Counts are per system, not per person; population figures are available only for systems serving more than 25,000 people (about 7,489,710 people across those systems here). UCMR 5 was a one-time national monitoring programme (2023–2025). The results are a snapshot at the system's entry points or taps on the sample dates, not a continuous measurement and not a compliance record.
| System | People served | UCMR 5 result |
|---|---|---|
| Chicago Chicago | 2,721,308 | None detected (below the reporting level) |
Pages for these are being added in stages. The data for all 487 systems is in the public dataset.
| System | People served | UCMR 5 result |
|---|---|---|
| Aurora Aurora | 183,000 | Detected, below the 2024 limit |
| Joliet Joliet | 160,000 | None detected (below the reporting level) |
| Naperville Naperville | 156,406 | None detected (below the reporting level) |
| Il American-Champaign Il American-Champaign | 150,000 | None detected (below the reporting level) |
| Rockford, Il Rockford, Il | 147,051 | Detected, below the 2024 limit |
| Il American-Peoria Il American-Peoria | 137,575 | Above the 2024 limit in at least one sample |
| Il American-East St Louis Il American-East St Louis | 131,368 | None detected (below the reporting level) |
| Springfield, Il Springfield, Il | 117,444 | None detected (below the reporting level) |
| Elgin, Il Elgin, Il | 114,797 | None detected (below the reporting level) |
| Waukegan Waukegan | 87,149 | None detected (below the reporting level) |
| Cicero Cicero | 83,000 | None detected (below the reporting level) |
| Aqua Illinois-Kankakee Aqua Illinois-Kankakee | 80,000 | None detected (below the reporting level) |
| Bloomington, Il Bloomington, Il | 79,000 | None detected (below the reporting level) |
| Decatur Decatur | 76,122 | None detected (below the reporting level) |
| Schaumburg Schaumburg | 75,750 | None detected (below the reporting level) |
| Evanston Evanston | 74,486 | None detected (below the reporting level) |
| Il American-West Suburban Il American-West Suburban | 73,978 | None detected (below the reporting level) |
| Arlington Heights Arlington Heights | 73,320 | None detected (below the reporting level) |
| Palatine Palatine | 70,875 | None detected (below the reporting level) |
| Skokie Skokie | 66,422 | None detected (below the reporting level) |
| Des Plaines Des Plaines | 60,675 | None detected (below the reporting level) |
| Oak Lawn Oak Lawn | 58,362 | None detected (below the reporting level) |
| Orland Park Orland Park | 58,020 | None detected (below the reporting level) |
| Berwyn Berwyn | 57,250 | None detected (below the reporting level) |
| Tinley Park Tinley Park | 56,703 | None detected (below the reporting level) |