Entergy Arkansas, LLC- Ouachita Plant

NPDES permit LA0112780 · Major NON-POTW · effective, expires 2029-10-31 · EPA's file as of 2026-09-19

Check this month's numbers before you file

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

0values over a limit
0required values missing, on 0 form(s)
0of 85 forms filed late

Last period with anything received: 2026-08-31.

Reporting

Reports are due about 28 days after each monitoring period ends (the most common figure among LA permits in EPA's filings — check your permit).

Limits in force (90)

OutfallParameterStatisticLimitMonths
001Temperature, water deg. fahrenheitMO AVG report only all year
001Temperature, water deg. fahrenheitDAILY MX <= 99 deg F all year
001pHINST MIN report only all year
001pHINST MAX report only all year
001Chromium, total [as Cr]MO AVG <= .2 mg/L all year
001Chromium, total [as Cr]DAILY MX <= .2 mg/L all year
001Zinc, total [as Zn]MO AVG <= 1 mg/L all year
001Zinc, total [as Zn]DAILY MX <= 1 mg/L all year
001Whole effluent toxicity - retest #1MO AV MN report only all year
001Whole effluent toxicity - retest #148HR MIN report only all year
001Whole effluent toxicity - retest #148HR MIN report only all year
001Whole effluent toxicity - retest #1MO AV MN report only all year
001Whole effluent toxicity - retest #2MO AV MN report only all year
001Whole effluent toxicity - retest #248HR MIN report only all year
001Whole effluent toxicity - retest #248HR MIN report only all year
001Whole effluent toxicity - retest #2MO AV MN report only all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantDAILY MX report only all year
001Chlorine, free availableMO AVG <= .2 mg/L all year
001Chlorine, free availableDAILY MX <= .5 mg/L all year
001Whole Effluent Toxicity - Retest #3MO AV MN report only all year
001Whole Effluent Toxicity - Retest #348HR MIN report only all year
001Whole Effluent Toxicity - Retest #348HR MIN report only all year
001Whole Effluent Toxicity - Retest #3MO AV MN report only all year
001pH range excursions, > 60 minutesMO TOTAL <= 0 occur/mo all year
001pH range excursions, monthly total accumMO TOTAL <= 446 min all year
001Low Flow Pass/Fail Static Renewal 48Hr Acute Daphnia pulex48HR MIN report only all year
001Low Flow Pass/Fail Static Renewal 48Hr Acute Daphnia pulexMO AV MN report only all year
001LF Pass/Fail Static Renewal 48Hr Acute Pimephales promelasMO AV MN report only all year
001LF Pass/Fail Static Renewal 48Hr Acute Pimephales promelas48HR MIN report only all year
001NOAEC Lethal Statis Renewal 48 Hr Acute Daphnia pulex48HR MIN report only all year
001NOAEC Lethal Statis Renewal 48 Hr Acute Daphnia pulexMO AV MN report only all year
001NOAEC Lethal Static Renewal 48Hr acute Pimephales promelasMO AV MN report only all year
001NOAEC Lethal Static Renewal 48Hr acute Pimephales promelas48HR MIN report only all year
001Coef Of Var Static Renewal 48Hr Acute D. pulexMAXIMUM report only all year
001Coef Of Var Static Renewal 48Hr Acute Pimephales promelasMAXIMUM report only all year
002pHINST MIN >= 6 SU all year
002pHINST MAX <= 9 SU all year
002Solids, total suspendedMO AVG <= 30 mg/L all year
002Solids, total suspendedDAILY MX <= 100 mg/L all year
002Oil & GreaseMO AVG <= 15 mg/L all year
002Oil & GreaseDAILY MX <= 20 mg/L all year
002Copper, total [as Cu]MO AVG report only all year
002Copper, total [as Cu]DAILY MX report only all year
002Flow, in conduit or thru treatment plantMO AVG report only all year
002Flow, in conduit or thru treatment plantDAILY MX report only all year
003pHINST MIN >= 6 SU all year
003pHINST MAX <= 9 SU all year
003Oil & GreaseDAILY MX <= 15 mg/L all year
003Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
003Flow, in conduit or thru treatment plantMO AVG report only all year
003Flow, in conduit or thru treatment plantDAILY MX report only all year
003Mercury, total [as Hg]MO AVG report only all year
003Mercury, total [as Hg]DAILY MX report only all year
004pHINST MIN >= 6 SU all year
004pHINST MAX <= 9 SU all year
004Oil & GreaseDAILY MX <= 15 mg/L all year
004Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
004Flow, in conduit or thru treatment plantMO AVG report only all year
004Flow, in conduit or thru treatment plantDAILY MX report only all year
005Flow, in conduit or thru treatment plantMO AVG report only all year
005Flow, in conduit or thru treatment plantDAILY MX report only all year
201pHINST MIN >= 6 SU all year
201pHINST MAX <= 9 SU all year
201Solids, total suspendedDAILY MX report only all year
201Solids, total suspendedDAILY MX <= 90 mg/L all year
201Solids, total suspendedDAILY MX <= 90 mg/L all year
201Oil & GreaseDAILY MX <= 15 mg/L all year
201Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
201Lead, total [as Pb]DAILY MX <= 50 ug/L all year
201BenzeneDAILY MX <= 50 ug/L all year
201BTEXDAILY MX <= 250 ug/L all year
201Flow, in conduit or thru treatment plantMO AVG report only all year
201Flow, in conduit or thru treatment plantDAILY MX report only all year
301Oxygen demand, chem. [high level] [COD]MO AVG <= 200 mg/L all year
301Oxygen demand, chem. [high level] [COD]DAILY MX <= 300 mg/L all year
301pHINST MIN >= 6 SU all year
301pHINST MAX <= 9 SU all year
301Solids, total suspendedMO AVG <= 30 mg/L all year
301Solids, total suspendedDAILY MX <= 100 mg/L all year
301Oil & GreaseMO AVG <= 15 mg/L all year
301Oil & GreaseDAILY MX <= 20 mg/L all year
301Copper, total [as Cu]MO AVG <= 1 mg/L all year
301Copper, total [as Cu]DAILY MX <= 1 mg/L all year
301Iron, total [as Fe]MO AVG <= 1 mg/L all year
301Iron, total [as Fe]DAILY MX <= 1 mg/L all year
301Flow, in conduit or thru treatment plantMO AVG report only all year
301Flow, in conduit or thru treatment plantDAILY MX report only all year
IT01Flow, in conduit or thru treatment plantMO AVG report only all year
IT01Flow, in conduit or thru treatment plantDAILY MX 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