STP NUCLEAR OPERATING COMPANY

NPDES permit TX0064947 · Major NON-POTW · effective, expires 2030-02-14 · EPA's file as of 2026-09-19

Check this month's numbers before you file
Watch this permit — $79 a month. Every Monday, from EPA's newest files: the next report due and when, whether EPA's file holds your last one, any change to this permit's limits or status, and the renewal date.

EPA's record, 2025-09-01 to 2026-08-31

0values over a limit
0required values missing, on 0 form(s)
0of 77 forms filed late

Last period with anything received: 2026-07-31.

Reporting

Reports are due about 20 days after each monitoring period ends (the most common figure among TX permits in EPA's filings — check your permit).

Limits in force (117)

OutfallParameterStatisticLimitMonths
001Temperature, water deg. fahrenheitDAILY AV <= 95 deg F all year
001Temperature, water deg. fahrenheitDAILY MX <= 97 deg F all year
001pHMINIMUM >= 6 SU all year
001pHMAXIMUM <= 9 SU all year
001Flow, in conduit or thru treatment plantDAILY AV <= 144 MGD all year
001Flow, in conduit or thru treatment plantDAILY MX <= 200 MGD all year
001Chlorine, total residualDAILY MX <= .05 mg/L all year
001EnterococciDAILY AV <= 35 CFU/100mL all year
001EnterococciDAILY MX <= 104 CFU/100mL all year
002Temperature, water deg. fahrenheitDAILY MX <= 95 deg F all year
002pHMINIMUM >= 6 SU all year
002pHMAXIMUM <= 9 SU all year
002Chlorine, total residualDAILY MX <= .05 mg/L all year
002Flow [dry weather]DAILY AV report only all year
002Flow [dry weather]DAILY MX report only all year
003Temperature, water deg. fahrenheitDAILY MX <= 95 deg F all year
003pHMINIMUM >= 6 SU all year
003pHMAXIMUM <= 9 SU all year
003Chlorine, total residualDAILY MX <= .05 mg/L all year
003Flow [dry weather]DAILY AV report only all year
003Flow [dry weather]DAILY MX report only all year
004Temperature, water deg. fahrenheitDAILY MX <= 95 deg F all year
004pHMINIMUM >= 6 SU all year
004pHMAXIMUM <= 9 SU all year
004Chlorine, total residualDAILY MX <= .05 mg/L all year
004Flow [dry weather]DAILY AV report only all year
004Flow [dry weather]DAILY MX report only all year
005Temperature, water deg. fahrenheitDAILY MX <= 95 deg F all year
005pHMINIMUM >= 6 SU all year
005pHMAXIMUM <= 9 SU all year
005Chlorine, total residualDAILY MX <= .05 mg/L all year
005Flow [dry weather]DAILY AV report only all year
005Flow [dry weather]DAILY MX report only all year
006Temperature, water deg. fahrenheitDAILY MX <= 95 deg F all year
006pHMINIMUM >= 6 SU all year
006pHMAXIMUM <= 9 SU all year
006Chlorine, total residualDAILY MX <= .05 mg/L all year
006Flow [dry weather]DAILY AV report only all year
006Flow [dry weather]DAILY MX report only all year
101pHMINIMUM >= 6 SU all year
101pHMAXIMUM <= 9 SU all year
101Solids, total suspendedDAILY AV <= 30 mg/L all year
101Solids, total suspendedDAILY MX <= 100 mg/L all year
101Oil & GreaseDAILY AV <= 15 mg/L all year
101Oil & GreaseDAILY MX <= 20 mg/L all year
101Flow, in conduit or thru treatment plantDAILY AV report only all year
101Flow, in conduit or thru treatment plantDAILY MX report only all year
201pHMINIMUM >= 6 SU all year
201pHMAXIMUM <= 9 SU all year
201Solids, total suspendedDAILY AV <= 30 mg/L all year
201Solids, total suspendedDAILY MX <= 100 mg/L all year
201Oil & GreaseDAILY AV <= 15 mg/L all year
201Oil & GreaseDAILY MX <= 20 mg/L all year
201Flow, in conduit or thru treatment plantDAILY AV report only all year
201Flow, in conduit or thru treatment plantDAILY MX report only all year
401BOD, 5-day, 20 deg. CDAILY AV <= 20 mg/L all year
401BOD, 5-day, 20 deg. CDAILY MX <= 45 mg/L all year
401pHMINIMUM >= 6 SU all year
401pHMAXIMUM <= 9 SU all year
401Solids, total suspendedDAILY AV <= 20 mg/L all year
401Solids, total suspendedDAILY MX <= 45 mg/L all year
401Flow, in conduit or thru treatment plantDAILY AV report only all year
401Flow, in conduit or thru treatment plantDAILY MX report only all year
401Chlorine, total residualMO MIN >= 1 mL/L all year
501pHMINIMUM >= 6 SU all year
501pHMAXIMUM <= 9 SU all year
501Solids, total suspendedDAILY AV <= 30 mg/L all year
501Solids, total suspendedDAILY MX <= 100 mg/L all year
501Oil & GreaseDAILY AV <= 15 mg/L all year
501Oil & GreaseDAILY MX <= 20 mg/L all year
501Copper, total [as Cu]DAILY AV <= .5 mg/L all year
501Copper, total [as Cu]DAILY MX <= 1 mg/L all year
501Iron, total [as Fe]DAILY AV <= 1 mg/L all year
501Iron, total [as Fe]DAILY MX <= 1 mg/L all year
501Flow, in conduit or thru treatment plantDAILY AV report only all year
501Flow, in conduit or thru treatment plantDAILY MX report only all year
601BOD, 5-day, 20 deg. CDAILY AV <= 20 mg/L all year
601BOD, 5-day, 20 deg. CDAILY MX <= 45 mg/L all year
601pHMINIMUM >= 6 SU all year
601pHMAXIMUM <= 9 SU all year
601Solids, total suspendedDAILY AV <= 20 mg/L all year
601Solids, total suspendedDAILY MX <= 45 mg/L all year
601Flow, in conduit or thru treatment plantDAILY AV report only all year
601Flow, in conduit or thru treatment plantDAILY MX report only all year
601Chlorine, total residualMO MIN >= 1 mg/L all year
TX1Whole effluent toxicity - retest #17 DA MIN report only all year
TX1Whole effluent toxicity - retest #1MO AV MN report only all year
TX1Whole effluent toxicity - retest #27 DA MIN report only all year
TX1Whole effluent toxicity - retest #2MO AV MN report only all year
TX1Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)7 DA MIN report only all year
TX1Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)MO AV MN report only all year
TX1Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TX1NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)7 DA MIN report only all year
TX1NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)MO AV MN report only all year
TX1NOEC Lethal Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1NOEC Lethal Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TX1NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)7 DA MIN report only all year
TX1NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)MO AV MN report only all year
TX1NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TX1Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)7 DA MIN report only all year
TX1Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)MO AV MN report only all year
TX1Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TX1LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)7 DA MIN report only all year
TX1LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)MO AV MN report only all year
TX1LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TX1LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)7 DA MIN report only all year
TX1LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)MO AV MN report only all year
TX1LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidia7 DA MIN report only all year
TX1LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidiaMO AV MN report only all year
TXAWhole effluent toxicity - retest #1SINGSAMP report only all year
TXAWhole effluent toxicity - retest #2SINGSAMP report only all year
TXALC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia)SINGSAMP report only all year
TXALC50 Pass/Fail Static 24Hr Acute Menidia menidiaSINGSAMP report only all year

Built from EPA's ECHO bulk files. EPA's file, not the permit document, is the source: read your permit. Check a report before you file it · All states