Clean Water Act discharge permit · NPDES MI0023752
OWOSSO/MID SHIAWASSEE CO WWTP, Owosso, MI: NPDES MI0023752 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 26Pollutants under a numeric limit
- 10Pollutants with an effluent exceedance
OWOSSO/MID SHIAWASSEE CO WWTP, held by City of Owosso, holds NPDES permit MI0023752, which discharges to Shiawassee River. EPA’s file records it issued September 24, 2018 and expiring October 1, 2021. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | OWOSSO/MID SHIAWASSEE CO WWTP |
|---|---|
| Permittee as filed | City of Owosso |
| NPDES ID | MI0023752 |
| 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 | September 24, 2018 |
| Expiration date | October 1, 2021 |
| Issuing agency | State |
| Address | Owosso, MI 48867 |
| Receiving water | Shiawassee River |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Sawyer Drain-Shiawassee River (HUC 040802030207) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 33Pollutants on file
- 26Under a numeric limit
- 32With a violation of any kind
- 10With 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 |
|---|---|---|---|---|---|
| Solids, suspended percent removal | 2 | 19 | 17 | February 28, 2018 | 140% over the limit |
| Solids, total suspended | 4 | 15 | 15 | May 31, 2020 | 50% over the limit |
| Coliform, fecal general | 2 | 20 | 11 | May 31, 2024 | 305% over the limit |
| Phosphorus, total [as P] | 4 | 8 | 8 | May 31, 2017 | 14% over the limit |
| BOD, carbonaceous [5 day, 20 C] | 16 | 35 | 7 | August 31, 2024 | 120% over the limit |
| Nitrogen, ammonia total [as N] | 10 | 23 | 7 | October 31, 2025 | 70% over the limit |
| Hexachlorobenzene | 0 | 3 | 2 | November 30, 2023 | 1,400% over the limit |
| pH | 2 | 2 | 2 | November 30, 2011 | |
| BOD, carb-5 day, 20 deg C, percent removal | 2 | 1 | 1 | December 31, 2023 | 7% over the limit |
| Toxicity [chronic], Ceriodaphnia dubia | 0 | 1 | 1 | August 31, 2006 | 55% over the limit |
| Mercury, total [as Hg] | 6 | 28 | 0 | ||
| Oxygen, dissolved [DO] | 4 | 18 | 0 | ||
| Bromomethane | 0 | 12 | 0 | ||
| Perfluorooctanoic acid (PFOA) | 0 | 6 | 0 | ||
| Perfluorooctanesulfonate | 0 | 6 | 0 | ||
| Solids, total | 3 | 3 | 0 | ||
| Arsenic, dry weight | 3 | 3 | 0 | ||
| Selenium, dry weight | 3 | 3 | 0 | ||
| Copper, dry weight | 3 | 3 | 0 | ||
| Cadmium, dry weight | 3 | 3 | 0 | ||
| Nitrogen, total Kjeldahl | 3 | 3 | 0 | ||
| Molybdenum, sludge, total, dry weight [as Mo] | 3 | 3 | 0 | ||
| Zinc, sludge, total, dry weight [as Zn] | 3 | 3 | 0 | ||
| Lead, sludge, total, dry weight [as Pb] | 3 | 3 | 0 | ||
| Nickel, sludge, total, dry weight [as Ni] | 3 | 3 | 0 | ||
| Nitrogen, sludge, total, dry weight [as N] | 3 | 3 | 0 | ||
| Mercury, sludge, total, dry weight [as Hg] | 3 | 3 | 0 | ||
| Potassium, sludge, total, dry weight [as K] | 3 | 3 | 0 | ||
| Phosphorus, sludge, total, dry weight [as P] | 3 | 3 | 0 | ||
| Chloride [as Cl] | 0 | 2 | 0 | ||
| Sulfate, total [as SO4] | 0 | 2 | 0 | ||
| Chlorine, total residual | 1 | 1 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 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
- 7Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| March 9, 2026 | Failure to enforce standards, local limits, and reporting requirements (>15% SNC SIU) (Level II) | ST6 |
| March 9, 2026 | Monitoring Violations - Failure to Monitor for Non-Toxicity Requirements | ST6 |
| February 21, 2026 | Reporting Violations - Late Submittal of DMRs | ST6 |
| June 26, 2021 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| August 28, 2020 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| May 18, 2020 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| January 11, 2020 | Permit Violations - Discharge Without a Valid Permit | 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 September 14, 2026.