Illinois wastewater permits expiring in 2026
19 NPDES permits · 9 MGD combined average flow
19 publicly owned wastewater treatment plants in Illinois hold NPDES permits that expire during 2026, issued by Illinois Environmental Protection Agency. The table lists each plant with its permit number, expiry month, average flow, treatment technology and three-year violation count, in order of expiry.
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|
| Milford Stp, Village Of | Milford | 0.5 | IL0023272 | Mar 2026 | 1 |
| Kampsville Stp, Village Of | Kampsville | 0.03 | IL0055832 | Mar 2026 | 11 |
| Braidwood Stp, City Of | Braidwood | 1.23 | IL0054992 | May 2026 | 0 |
| Marengo Stp, City Of | Marengo | 0.42 | IL0020729 | May 2026 | 46 |
| New Lenox-STP #2, Village Of | New Lenox | 1.13 | IL0046264 | Jun 2026 | 6 |
| Minonk Stw, City Of | Minonk | 0.7 | IL0037818 | Jun 2026 | 0 |
| Nokomis Stp, City Of | Nokomis | 0.21 | IL0020206 | Jun 2026 | 96 |
| Warrensburg STP | Warrensburg | 0.06 | IL0034215 | Jun 2026 | 36 |
| Beecher Stp, Village Of | Beecher | 0.84 | IL0049522 | Jul 2026 | 0 |
| Bradford Stp, Village Of | Bradford | 0.14 | IL0022195 | Jul 2026 | 34 |
| Big Rock Stp, Village Of | Big Rock | 0.03 | IL0079464 | Jul 2026 | 0 |
| Manito Stp, Village Of | Manito | 0.06 | IL0035904 | Sep 2026 | 2 |
| Aqua Illinois - Grant Park STP | Grant Park | 0.35 | IL0050717 | Oct 2026 | 6 |
| Rushville Stp, City Of | Rushville | 0.71 | IL0021717 | Nov 2026 | 2 |
| Farmer City Stp, City Of | Farmer City | 0.4 | IL0022462 | Nov 2026 | 6 |
| Itasca, Village Of - Prospect Avenue WWTP | Itasca | 1.65 | IL0079073 | Dec 2026 | 5 |
| De Pue | Depue | 0.3 | IL0023523 | Dec 2026 | 28 |
| Ohlman STP | Ohlman | 0.02 | IL0032671 | Dec 2026 | 0 |
| Royal Lakes Stp, Village Of | Royal Lakes | 0.0034 | IL0071391 | Dec 2026 | 25 |
Illinois permit renewals in 2026: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026.
Wastewater terms: NPDES permit · POTW · Biological nutrient removal · Tertiary treatment · WWTP · Biosolids · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “NPDES permits expiring in 2026: Illinois wastewater plants.” Updated October 26, 2026. https://klarifi.io/facilities/illinois/permits-expiring/2026Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.