Clean Water Act discharge permit · NPDES MOG490027
MERCER QUARRY, Mercer, MO: NPDES MOG490027 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MinorDischarger class
- 5Pollutants under a numeric limit
- 1Pollutants with an effluent exceedance
MERCER QUARRY, held by MARTIN MARIETTA MATERIALS, INC., holds NPDES permit MOG490027, which discharges to Tributary To Muddy Cr.. EPA’s file records it issued June 1, 2022 and expiring April 30, 2027. 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 | MERCER QUARRY |
|---|---|
| Permittee as filed | MARTIN MARIETTA MATERIALS, INC. |
| NPDES ID | MOG490027 |
| Permit status | Effective |
| Permit type | Coverage under a general permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Industrial stormwater |
| Issued | June 1, 2022 |
| Expiration date | April 30, 2027 |
| Address | Mercer, MO 64661 |
| Receiving water | Tributary to Muddy Cr. |
| Subwatershed | Upper Muddy Creek (HUC 102801021101) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 5Pollutants on file
- 5Under a numeric limit
- 3With a violation of any kind
- 1With 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 |
|---|---|---|---|---|---|
| Oil and grease [soxhlet extr.] tot. | 4 | 3 | 1 | September 30, 2008 | 40% over the limit |
| pH | 4 | 2 | 0 | ||
| Solids, total suspended | 4 | 2 | 0 | ||
| Solids, settleable | 4 | 0 | 0 | ||
| Flow, in conduit or thru treatment plant | 4 | 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
- 1Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| May 22, 2024 | WW Storm Water Construction - Failure to develop any or adequate SWPPP/SWMP | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not yet 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
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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 MOG490027 there.
Nearby on the register
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- Every permit record in Missouri, A to Z
Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.