Clean Water Act discharge permit · NPDES MS0029521
ENTERGY MISS INC, GRAND GULF NUCLEAR STATION, Port Gibson, MS: NPDES MS0029521 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 12Pollutants under a numeric limit
- 7Pollutants with an effluent exceedance
ENTERGY MISS INC, GRAND GULF NUCLEAR STATION holds NPDES permit MS0029521, which discharges to By Open Ditch Into Lake Hamilton. EPA’s file records it issued July 2, 2019 and expiring June 30, 2024. 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 | ENTERGY MISS INC, GRAND GULF NUCLEAR STATION |
|---|---|
| Permittee as filed | ENTERGY MISS INC, GRAND GULF NUCLEAR STATION |
| NPDES ID | MS0029521 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | July 2, 2019 |
| Expiration date | June 30, 2024 |
| Issuing agency | MDEQ |
| Address | Port Gibson, MS 39150 |
| Receiving water | BY OPEN DITCH INTO LAKE HAMILTON |
| Subwatershed | 080601000200 (HUC 080601000200) |
| NAICS | 221113 – Nuclear Electric Power Generation |
| SIC | 4911 – Electric Services |
| Other EPA IDs (FRS) | RCRA handler MSD000644617; ICIS-AIR source MS0000002802100023 |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download; cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 13Pollutants on file
- 12Under a numeric limit
- 9With 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 |
|---|---|---|---|---|---|
| Zinc, total recoverable | 10 | 20 | 7 | March 31, 2015 | 117% over the limit |
| Solids, total suspended | 14 | 7 | 7 | April 30, 2013 | 44% over the limit |
| Chlorine, total residual | 6 | 6 | 4 | December 31, 2013 | 340% over the limit |
| pH | 10 | 4 | 4 | December 31, 2012 | |
| Chlorination duration | 4 | 7 | 3 | March 31, 2013 | 33% over the limit |
| Chlorine, free available | 8 | 10 | 2 | September 30, 2018 | 158% over the limit |
| Oil & grease [freon extr.-IR meth] tot, RC | 0 | 1 | 1 | March 31, 2004 | 75% over the limit |
| Flow, in conduit or thru treatment plant | 22 | 10 | 0 | ||
| Temperature, water deg. fahrenheit | 2 | 2 | 0 | ||
| Oil & Grease | 8 | 0 | 0 | ||
| Chromium, total recoverable | 6 | 0 | 0 | ||
| BOD, 5-day, 20 deg. C | 2 | 0 | 0 | ||
| E. coli | 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
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES MS0029521.
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, MS0029521.
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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 MS0029521 there.
Nearby on the register
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- Every permit record in Port Gibson, A to Z
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- Every permit record in Mississippi, A to Z
Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.