Clean Water Act discharge permit · NPDES TX0123749
GRAND MISSION MUD 1 WWTP, Katy, TX: NPDES TX0123749 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 55Pollutants under a numeric limit
- 5Pollutants with an effluent exceedance
GRAND MISSION MUD 1 WWTP, held by GRAND MISSION MUD 1, holds NPDES permit TX0123749, which discharges to Long Point Slough; Buffalo Bayou. EPA’s file records it issued September 13, 2019 and expiring September 13, 2024. 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 | GRAND MISSION MUD 1 WWTP |
|---|---|
| Permittee as filed | GRAND MISSION MUD 1 |
| NPDES ID | TX0123749 |
| 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 13, 2019 |
| Expiration date | September 13, 2024 |
| Address | Katy, TX 77407 |
| Receiving water | LONG POINT SLOUGH; BUFFALO BAYOU |
| Subwatershed | Keegans Bayou-Brays Bayou (HUC 120401040401) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 55Pollutants on file
- 55Under a numeric limit
- 10With a violation of any kind
- 5With 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 |
|---|---|---|---|---|---|
| E. coli | 2 | 42 | 36 | July 31, 2026 | 5,917% over the limit |
| Nitrogen, ammonia total [as N] | 6 | 9 | 6 | December 31, 2009 | 160% over the limit |
| pH | 3 | 4 | 2 | June 30, 2013 | |
| Flow, in conduit or thru treatment plant | 6 | 6 | 1 | August 31, 2017 | 2% over the limit |
| Oxygen, dissolved [DO] | 1 | 2 | 1 | August 31, 2007 | 8% over the limit |
| BOD, carbonaceous [5 day, 20 C] | 6 | 19 | 0 | ||
| Solids, total suspended | 6 | 3 | 0 | ||
| Chlorine, total residual | 2 | 2 | 0 | ||
| Annual sludge production, total | 1 | 1 | 0 | ||
| Annual amt sludge disposed in landfill | 1 | 1 | 0 | ||
| Arsenic, dry weight | 5 | 0 | 0 | ||
| Chromium, sludge, total, dry weight [as Cr] | 5 | 0 | 0 | ||
| Selenium, dry weight | 3 | 0 | 0 | ||
| Whole effluent toxicity - retest #1 | 3 | 0 | 0 | ||
| Whole effluent toxicity - retest #2 | 3 | 0 | 0 | ||
| Copper, dry weight | 3 | 0 | 0 | ||
| Cadmium, dry weight | 3 | 0 | 0 | ||
| Molybdenum, sludge, total, dry weight [as Mo] | 3 | 0 | 0 | ||
| Zinc, sludge, total, dry weight [as Zn] | 3 | 0 | 0 | ||
| Lead, sludge, total, dry weight [as Pb] | 3 | 0 | 0 | ||
| Nickel, sludge, total, dry weight [as Ni] | 3 | 0 | 0 | ||
| Mercury, sludge, total, dry weight [as Hg] | 3 | 0 | 0 | ||
| Nickel, total [as Ni] | 2 | 0 | 0 | ||
| Whole effluent toxicity | 2 | 0 | 0 | ||
| Level of pathogen requirements achieved | 2 | 0 | 0 | ||
| Description of pathogen option used | 2 | 0 | 0 | ||
| Vector attraction reduction alternative used | 2 | 0 | 0 | ||
| Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas | 2 | 0 | 0 | ||
| NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas | 2 | 0 | 0 | ||
| NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas | 2 | 0 | 0 | ||
| Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Pinephales promelas | 2 | 0 | 0 | ||
| LOEC Lethal Survival Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| LOEC Lethal Survival Static Renewal 7 Day Chronic Pimephales promelas | 2 | 0 | 0 | ||
| LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Ceriodaphnia dubia | 2 | 0 | 0 | ||
| LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Pimephales promelas | 2 | 0 | 0 | ||
| Fecal coliform | 1 | 0 | 0 | ||
| Polychlorinated biphenyls [PCBs] | 1 | 0 | 0 | ||
| Toxicity characteristic leaching procedure | 1 | 0 | 0 | ||
| Annual whole sludge application rate | 1 | 0 | 0 | ||
| Ann. amt sludge disposed by other method | 1 | 0 | 0 | ||
| Annual amt of sludge incinerated | 1 | 0 | 0 | ||
| Annual amount of sludge land applied | 1 | 0 | 0 | ||
| Annual amt. sludge disposed surface unit | 1 | 0 | 0 | ||
| Annual amt sludge transported interstate | 1 | 0 | 0 | ||
| Unit w/liner/leachate collection system | 1 | 0 | 0 | ||
| Compliance w/part 258 sludge requirement | 1 | 0 | 0 | ||
| Boundary areas | 1 | 0 | 0 | ||
| Salmonella | 1 | 0 | 0 | ||
| Pollutant table from 503.13 | 1 | 0 | 0 | ||
| LC50 Pass/Fail Static 24Hr Acute D. Pulex | 1 | 0 | 0 | ||
| LC50 Pass/Fail Static 24Hr Acute Pimephales promelas | 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
- 3Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| May 14, 2025 | Permit Violations - Violation Specified in Comment | ST6 |
| July 30, 2019 | Permit Violations - Violation Specified in Comment | ST6 |
| April 4, 2017 | Permit Violations - Violation Specified in Comment | 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.
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.