Clean Water Act discharge permit · NPDES MO0028720
O'FALLON WWTP, O'Fallon, MO: NPDES MO0028720 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MajorDischarger class
- 15Pollutants under a numeric limit
- 11Pollutants with an effluent exceedance
O'FALLON WWTP, held by City of O'Fallon, holds NPDES permit MO0028720, which discharges to Tributary To Peruque Creek. EPA’s file records it issued July 22, 2020 and expiring March 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 WWTP |
|---|---|
| Permittee as filed | City of O'Fallon |
| NPDES ID | MO0028720 |
| Permit status | Effective |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | July 22, 2020 |
| Expiration date | March 31, 2025 |
| Address | O'Fallon, MO 63366 |
| Receiving water | Tributary to Peruque Creek |
| Subwatershed | Peruque Creek (HUC 071100090102) |
| Program components on file | Biosolids, POTW, Pretreatment |
| 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
- 35Pollutants on file
- 15Under a numeric limit
- 30With a violation of any kind
- 11With 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 | 0 | 99 | 9 | August 31, 2006 | 99,999% over the limit |
| Nitrogen, ammonia total [as N] | 4 | 68 | 8 | October 31, 2019 | 85% over the limit |
| E. coli, colony forming units [CFU] | 0 | 19 | 7 | July 31, 2020 | 427% over the limit |
| Oil and grease [soxhlet extr.] tot. | 2 | 18 | 4 | March 31, 2006 | 108% over the limit |
| E. coli | 2 | 4 | 4 | April 30, 2021 | 284% over the limit |
| Solids, settleable | 0 | 4 | 4 | March 31, 2008 | 900% over the limit |
| Solids, total suspended | 3 | 66 | 3 | December 31, 2007 | 16% over the limit |
| pH | 2 | 73 | 2 | March 31, 2007 | |
| Toxicity [acute], Pimephales promelas [Fathead Minnow] | 1 | 3 | 2 | December 31, 2022 | 140% over the limit |
| Copper, dissolved [as Cu] | 0 | 2 | 2 | August 31, 2006 | 277% over the limit |
| Zinc, dissolved [as Zn] | 0 | 1 | 1 | August 31, 2006 | 23% over the limit |
| CBOD5+NH3-N | 0 | 138 | 0 | ||
| Hardness, total [as CaCO3] | 0 | 60 | 0 | ||
| Oxygen, dissolved [DO] | 0 | 50 | 0 | ||
| Nitrite + Nitrate total [as N] | 4 | 49 | 0 | ||
| Solids, total dissolved- 180 deg. C | 0 | 47 | 0 | ||
| BOD, 5-day, 20 deg. C | 0 | 46 | 0 | ||
| Phosphorus, total [as P] | 4 | 20 | 0 | ||
| Nitrogen, total [as N] | 0 | 20 | 0 | ||
| BOD, carbonaceous [5 day, 20 C] | 0 | 15 | 0 | ||
| Zinc, total recoverable | 0 | 14 | 0 | ||
| Copper, total recoverable | 0 | 14 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 10 | 0 | ||
| Pass/Fail Static 48Hr Acute Ceriodaphnia dubia | 0 | 5 | 0 | ||
| LC50 Static 48Hr Acute Pimephales promelas | 0 | 5 | 0 | ||
| Mercury, total recoverable | 0 | 4 | 0 | ||
| Toxicity [acute], Ceriodaphnia dubia | 1 | 1 | 0 | ||
| Temperature, water deg. centigrade | 0 | 1 | 0 | ||
| Toxicity [chronic], Ceriodaphnia dubia | 0 | 1 | 0 | ||
| Toxicity [chronic], Pimephales promelas [Fathead Minnow] | 0 | 1 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 4 | 0 | 0 | ||
| BOD, carbonaceous [20 day, 20 C] | 3 | 0 | 0 | ||
| Methylene chloride | 2 | 0 | 0 | ||
| BOD, 5 day carbonaceous, % rmvl, wet | 1 | 0 | 0 | ||
| Solids, suspended percent removal | 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
- 11Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| May 14, 2026 | Reporting Violations - Failure to Submit DMRs | ST6 |
| December 31, 2025 | Permit Violations - Violation Specified in Comment | ST6 |
| December 31, 2025 | Pretreatment - Failure to Develop/Enforce Standards | ST6 |
| November 27, 2024 | Permit Violations - Violation Specified in Comment | ST6 |
| November 27, 2024 | Pretreatment - Failure to Develop/Enforce Standards | ST6 |
| October 14, 2021 | Pretreatment - Failure to Develop/Enforce Standards | ST6 |
| October 10, 2019 | Permit Violations - Violation Specified in Comment | ST6 |
| October 10, 2019 | Pretreatment - Failure to Develop/Enforce Standards | ST6 |
| July 26, 2019 | Permit Violations - Violation Specified in Comment | ST6 |
| July 26, 2019 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
| January 23, 2018 | Pretreatment - Failure to Develop/Enforce Standards | 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.