Clean Water Act discharge permit · NPDES TX0064947

SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION, Bay City, TX: NPDES TX0064947 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MajorDischarger class
27Pollutants under a numeric limit
0Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION, held by STP NUCLEAR OPERATING COMPANY, holds NPDES permit TX0064947, which discharges to Colorado River;Plant Area Drainage Ditch. EPA’s file records it issued February 21, 2020 and expiring February 21, 2025.

SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION, Bay City, Texas: Individual permit TX0064947, held by STP NUCLEAR OPERATING COMPANY; Administratively continued (past its expiration date and still in force until reissued); issued February 21, 2020, term to February 21, 2025; discharges to COLORADO RIVER;PLANT AREA DRAINAGE DITCH.

Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidia: 2 limits, 2 violations of any kind, 0 effluent exceedances.
pH: 22 limits, 0 violations of any kind, 0 effluent exceedances.
Flow, in conduit or thru treatment plant: 13 limits, 0 violations of any kind, 0 effluent exceedances.
Solids, total suspended: 10 limits, 0 violations of any kind, 0 effluent exceedances.
Flow [dry weather]: 10 limits, 0 violations of any kind, 0 effluent exceedances.
Chlorine, total residual: 8 limits, 0 violations of any kind, 0 effluent exceedances.
Temperature, water deg. fahrenheit: 7 limits, 0 violations of any kind, 0 effluent exceedances.
Oil & Grease: 6 limits, 0 violations of any kind, 0 effluent exceedances.
BOD, 5-day, 20 deg. C: 4 limits, 0 violations of any kind, 0 effluent exceedances.
Whole effluent toxicity - retest #1: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Whole effluent toxicity - retest #2: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Copper, total [as Cu]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Iron, total [as Fe]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Enterococci: 2 limits, 0 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia): 1 limit, 0 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Menidia menidia: 1 limit, 0 violations of any kind, 0 effluent exceedances.

SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION among its neighbors

EPA’s permit file holds 12 discharge permits in the Colorado River-Gulf of Mexico subwatershed (HUC 120903020207), TX0064947 among them. Its county holds 66, 5 of them major permits; TX0064947 is a major permit.

Other permits in the Colorado River-Gulf of Mexico subwatershed (HUC 120903020207)

AUSTIN COLONY SUBDIVISION WWTP, Matagorda: TX0135810, minor permit, permit term to December 1, 2019
BAY CITY LMA, Bay City: TX0140520, minor permit, discharging to Colorado River Tidal, permit term to May 24, 2026
BAY CITY LMA, Bay City: TXR05EZ46, minor permit, permit term to August 13, 2026
DUFFY BESS AND SUBSTATION, Bay City: TXR1593WQ, minor permit, discharging to WILSON CREEK, permit term to March 4, 2028
DUFFY BESS AND SUBSTATION ACCESS ROAD, Bay City: TXR1501WK, minor permit, discharging to WILSON CREEK, permit term to March 4, 2028
EQUISTAR MATAGORDA PLANT, Bay City: TXR05FR67, minor permit, permit term to August 13, 2026
MATAGORDA BAY NATURE PARK AND PRESERVE WWTP, Matagorda: TX0125521, minor permit, discharging to OLD COLORADO RIVER CHANNEL, GULF OF MEXICO, permit term to March 17, 2025
OQ CHEMICALS, Bay City: TXR05V929, minor permit, permit term to August 13, 2026
OXEA BAY CITY PLANT, Bay City: TX0006017, major permit, discharging to UNDERGROUND PIPE COLORADO RIVER, permit term to December 1, 2019
ROEHM AMERICA BAY CITY SITE, Bay City: TXR1526LZ, minor permit, discharging to COLORADO RIVER TIDAL, permit term to March 5, 2023

Identity

Facility as filed	SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION
Permittee as filed	STP NUCLEAR OPERATING COMPANY
NPDES ID	TX0064947
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	February 21, 2020
Expiration date	February 21, 2025
Address	Bay City, TX 77483
Receiving water	COLORADO RIVER;PLANT AREA DRAINAGE DITCH
Subwatershed	Colorado River-Gulf of Mexico (HUC 120903020207)
SIC	4911 – Electric Services

Effluent limits and exceedances

27Pollutants on file
27Under a numeric limit
12With 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
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	2	2
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidia	2	2
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	2
NOEC Lethal Static Renewal 7 Day Chronic Menidia menidia	2	2
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	2
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia	2	2
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	2
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia	2	2
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	2
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidia	2	2
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	2	2
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidia	2	2
pH	22	0
Flow, in conduit or thru treatment plant	13	0
Solids, total suspended	10	0
Flow [dry weather]	10	0
Chlorine, total residual	8	0
Temperature, water deg. fahrenheit	7	0
Oil & Grease	6	0
BOD, 5-day, 20 deg. C	4	0
Whole effluent toxicity - retest #1	3	0
Whole effluent toxicity - retest #2	3	0
Copper, total [as Cu]	2	0
Iron, total [as Fe]	2	0
Enterococci	2	0
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia)	1	0
LC50 Pass/Fail Static 24Hr Acute Menidia menidia	1	0

EPA’s effluent violation file records no exceedance of a numeric limit for NPDES TX0064947.

Inspections, violations and enforcement

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES TX0064947.

Inspections

EPA’s inspection file holds no inspection for NPDES TX0064947.

Formal enforcement and penalties

0 formal actions, 0 of them with a penalty assessed. Federal and state penalties are separate figures from separate authorities and are shown as each was filed, never added together.

Informal enforcement

EPA’s informal enforcement file holds no action for NPDES TX0064947.

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Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.

This public-records page covers Clean Water Act discharge permit NPDES TX0064947 for the SOUTH TEXAS PRJOECT ELECTRIC GENERATING STATION in Bay City, TX, held by STP NUCLEAR OPERATING COMPANY, with the permit listed as administratively continued and classed as a Major Discharger. The page reports 27 as the discharger class, 0 pollutants under a numeric limit, and 0 pollutants with an effluent exceedance, with the permit recorded as issued February 21, 2020 and expiring February 21, 2025.