Clean Water Act discharge permit · NPDES IL0021636
O'FALLON STP, CITY OF, O'Fallon, IL: NPDES IL0021636 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 32Pollutants under a numeric limit
- 7Pollutants with an effluent exceedance
O'FALLON STP, CITY OF, held by O'FALLON, CITY OF, holds NPDES permit IL0021636, which discharges to Silver Creek Ditch. EPA’s file records it issued May 14, 2020 and expiring May 31, 2025. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | O'FALLON STP, CITY OF |
|---|---|
| Permittee as filed | O'FALLON, CITY OF |
| NPDES ID | IL0021636 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | May 14, 2020 |
| Expiration date | May 31, 2025 |
| Address | O'Fallon, IL 62269 |
| Receiving water | SILVER CREEK DITCH |
| Subwatershed | Mill Creek-Silver Creek (HUC 071402040509) |
| Program components on file | Biosolids, POTW |
| SIC | 4952 – Sewerage Systems |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download.
Effluent limits and exceedances
- 32Pollutants on file
- 32Under a numeric limit
- 12With a violation of any kind
- 7With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Coliform, fecal general | 2 | 20 | 19 | August 31, 2011 | 7,400% over the limit |
| Nitrogen, ammonia total [as N] | 16 | 19 | 9 | June 30, 2018 | 148% over the limit |
| Zinc, total [as Zn] | 4 | 15 | 7 | November 30, 2019 | 29% over the limit |
| Solids, total suspended | 5 | 16 | 6 | February 28, 2019 | 1,533% over the limit |
| Chlorine, total residual | 1 | 15 | 2 | September 30, 2010 | 200% over the limit |
| BOD, carbonaceous [5 day, 20 C] | 4 | 10 | 2 | February 28, 2009 | 355% over the limit |
| Oxygen, dissolved [DO] | 5 | 4 | 2 | October 31, 2009 | 32% over the limit |
| Flow, in conduit or thru treatment plant | 4 | 10 | 0 | ||
| pH | 2 | 4 | 0 | ||
| BOD, 5-day, 20 deg. C | 1 | 2 | 0 | ||
| Copper, total [as Cu] | 2 | 1 | 0 | ||
| Silver, total [as Ag] | 2 | 1 | 0 | ||
| Oil & Grease | 2 | 0 | 0 | ||
| Cyanide, total [as CN] | 2 | 0 | 0 | ||
| Cyanide, free [amenable to chlorination] | 2 | 0 | 0 | ||
| Fluoride, total [as F] | 2 | 0 | 0 | ||
| Arsenic, total [as As] | 2 | 0 | 0 | ||
| Barium, total [as Ba] | 2 | 0 | 0 | ||
| Cadmium, total [as Cd] | 2 | 0 | 0 | ||
| Chromium, hexavalent [as Cr] | 2 | 0 | 0 | ||
| Chromium, total [as Cr] | 2 | 0 | 0 | ||
| Iron, total [as Fe] | 2 | 0 | 0 | ||
| Iron, dissolved [as Fe] | 2 | 0 | 0 | ||
| Lead, total [as Pb] | 2 | 0 | 0 | ||
| Manganese, total [as Mn] | 2 | 0 | 0 | ||
| Nickel, total [as Ni] | 2 | 0 | 0 | ||
| Selenium, total [as Se] | 2 | 0 | 0 | ||
| Phenolics, total recoverable | 2 | 0 | 0 | ||
| Mercury, total [as Hg] | 2 | 0 | 0 | ||
| Nitrogen, total [as N] | 1 | 0 | 0 | ||
| Phosphorus, total [as P] | 1 | 0 | 0 | ||
| Coliform, fecal - % samples exceeding limit | 1 | 0 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 2Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| April 19, 2025 | Wet-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment | ST6 |
| March 15, 2025 | Wet-weather SSO discharge to waters of the U.S. that may endanger health or the environment | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.