Clean Water Act discharge permit · NPDES MOG491270
SEMO OPERATING CO., Marston, MO: NPDES MOG491270 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 0Pollutants under a numeric limit
- 0Pollutants with an effluent exceedance
SEMO OPERATING CO., held by SEMO Operating Company LLC, holds NPDES permit MOG491270, which discharges to Tributary To Portage Open Bay. EPA’s file records it issued May 1, 2017 and expiring April 30, 2022. 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 | SEMO OPERATING CO. |
|---|---|
| Permittee as filed | SEMO Operating Company LLC |
| NPDES ID | MOG491270 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Coverage under a general permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Industrial stormwater |
| Issued | May 1, 2017 |
| Expiration date | April 30, 2022 |
| Address | Marston, MO 63866 |
| Receiving water | Tributary to Portage Open Bay |
| Subwatershed | Portage Open Bay (HUC 080202040608) |
| NAICS | 212312 – Crushed and Broken Limestone Mining and Quarrying |
| SIC | 3273 – Ready-Mixed Concrete |
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
- 5Pollutants on file
- 0Under a numeric limit
- 5With a violation of any kind
- 0With 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 |
|---|---|---|---|---|---|
| pH | 0 | 10 | 0 | ||
| Solids, total suspended | 0 | 10 | 0 | ||
| Solids, settleable | 0 | 10 | 0 | ||
| Oil and grease [soxhlet extr.] tot. | 0 | 10 | 0 | ||
| Flow, in conduit or thru treatment plant | 0 | 10 | 0 |
EPA’s effluent violation file records no exceedance of a numeric limit for NPDES MOG491270.
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
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES MOG491270.
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.
Watch this permit
One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, MOG491270.
Start the watch
- One permit holder — $99/month
- One watershed — $2,990/year
- One state — $4,990/year
- The whole register — $18,000/year
How we handle your data → Privacy
EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID MOG491270 there.
Nearby on the register
- Discharge permits in Marston
- Every permit record in Marston, A to Z
- Discharge permits in Missouri
- Every permit record in Missouri, A to Z
Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.