Casper, City of

NPDES permit WY0021920 · Major POTW · effective, expires 2030-10-31 · 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

7values over a limit
0required values missing, on 0 form(s)
0of 65 forms filed late

Last period with anything received: 2026-07-31. Most often over: BOD, 5-day, 20 deg. C (2), Solids, total suspended (2), Ammonia nitrogen, total, [as N] 30 day (2).

Reporting

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

Limits in force (81)

OutfallParameterStatisticLimitMonths
001Temperature, water deg. centigradeDAILY MX report only all year
001Oxygen, dissolved [DO]DAILY MX report only all year
001BOD, 5-day, 20 deg. CMO AVG <= 30 mg/L all year
001BOD, 5-day, 20 deg. CWKLY AVG <= 45 mg/L all year
001BOD, 5-day, 20 deg. CDAILY MX <= 90 mg/L all year
001BOD, 5-day, 20 deg. CDAILY MX report only all year
001BOD, 5-day, 20 deg. CMO AVG report only all year
001BOD, 5-day, 20 deg. CWKLY AVG report only all year
001pHINST MIN >= 6.5 SU all year
001pHINST MAX <= 9 SU all year
001Solids, total suspendedMO AVG <= 30 mg/L all year
001Solids, total suspendedWKLY AVG <= 45 mg/L all year
001Solids, total suspendedDAILY MX <= 90 mg/L all year
001Solids, total suspendedDAILY MX report only all year
001Solids, total suspendedMO AVG report only all year
001Solids, total suspendedWKLY AVG report only all year
001Nitrogen, total [as N]DAILY MX report only all year
001Ammonia nitrogen, total, [as N] 30 dayMO AVG <= 10.19 mg/L Jan, Feb, Mar, Apr, Oct, Nov, Dec
001Ammonia nitrogen, total, [as N] 30 dayMO AVG <= 4.24 mg/L May, Jun, Jul, Aug, Sep
001Ammonia nitrogen, total, [as N] 30 dayDAILY MX <= 247.02 mg/L Jan, Feb, Mar, Apr, Oct, Nov, Dec
001Ammonia nitrogen, total, [as N] 30 dayDAILY MX <= 13.12 mg/L May, Jun, Jul, Aug, Sep
001Nitrogen, Kjeldahl, total [as N]DAILY MX report only all year
001Nitrite + Nitrate total [as N]DAILY MX report only all year
001Phosphorus, total [as P]DAILY MX report only all year
001Selenium, total [as Se]DAILY MX report only all year
001Phosphate, ortho [as P]DAILY MX report only all year
001Chlorine, total residualDAILY MX <= .05 mg/L all year
001E. coliMO AVG <= 353 #/100mL May, Jun, Jul, Aug, Sep
001E. coliMO AVG <= 2501 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
001E. coliDAILY MX <= 770 #/100mL May, Jun, Jul, Aug, Sep
001E. coliDAILY MX <= 2501 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
001FlowDAILY MX report only all year
001FlowMO AVG <= 9 MGD all year
001BOD, 5-day, percent removalMO AV MN >= 85 % all year
001Solids, suspended percent removalMO AV MN >= 85 % all year
001Produced water, oil and greaseDAILY MX report only all year
001Produced water, oil and greaseDAILY MX <= 10 mg/L all year
001Pass/Fail Static Renewal 7Day Chronic Pimephales promelas7E <= 0 pass=0;fail=1 all year
001Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia7E <= 0 pass=0;fail=1 all year
002Temperature, water deg. centigradeDAILY MX report only all year
002Oxygen, dissolved [DO]DAILY MX report only all year
002BOD, 5-day, 20 deg. CMO AVG <= 30 mg/L all year
002BOD, 5-day, 20 deg. CWKLY AVG <= 45 mg/L all year
002BOD, 5-day, 20 deg. CDAILY MX <= 90 mg/L all year
002BOD, 5-day, 20 deg. CDAILY MX report only all year
002BOD, 5-day, 20 deg. CMO AVG report only all year
002BOD, 5-day, 20 deg. CWKLY AVG report only all year
002pHINST MIN >= 6.5 SU all year
002pHINST MAX <= 9 SU all year
002Solids, total suspendedMO AVG <= 30 mg/L all year
002Solids, total suspendedWKLY AVG <= 45 mg/L all year
002Solids, total suspendedDAILY MX <= 90 mg/L all year
002Solids, total suspendedDAILY MX report only all year
002Solids, total suspendedMO AVG report only all year
002Solids, total suspendedWKLY AVG report only all year
002Nitrogen, total [as N]DAILY MX report only all year
002Ammonia nitrogen, total, [as N] 30 dayMO AVG <= 10.19 mg/L Jan, Feb, Mar, Apr, Oct, Nov, Dec
002Ammonia nitrogen, total, [as N] 30 dayMO AVG <= 4.24 mg/L May, Jun, Jul, Aug, Sep
002Ammonia nitrogen, total, [as N] 30 dayDAILY MX <= 247.02 mg/L Jan, Feb, Mar, Apr, Oct, Nov, Dec
002Ammonia nitrogen, total, [as N] 30 dayDAILY MX <= 13.12 mg/L May, Jun, Jul, Aug, Sep
002Nitrogen, Kjeldahl, total [as N]DAILY MX report only all year
002Nitrite + Nitrate total [as N]DAILY MX report only all year
002Phosphorus, total [as P]DAILY MX report only all year
002Selenium, total recoverableDAILY MX report only all year
002Phosphate, ortho [as P]DAILY MX report only all year
002Chlorine, total residualDAILY MX <= .05 mg/L all year
002E. coliMO AVG <= 353 #/100mL May, Jun, Jul, Aug, Sep
002E. coliMO AVG <= 2501 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
002E. coliDAILY MX <= 770 #/100mL May, Jun, Jul, Aug, Sep
002E. coliDAILY MX <= 2501 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
002FlowDAILY MX report only all year
002FlowMO AVG <= 9 MGD all year
002BOD, 5-day, percent removalMO AV MN >= 85 % all year
002Solids, suspended percent removalMO AV MN >= 85 % all year
002Produced water, oil and greaseDAILY MX report only all year
002Produced water, oil and greaseDAILY MX <= 10 mg/L all year
002Pass/Fail Static Renewal 7Day Chronic Pimephales promelas7E <= 0 pass=0;fail=1 all year
002Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia7E <= 0 pass=0;fail=1 all year
DMP1Temperature, water deg. centigradeDAILY MX report only all year
DMP1pHINST MIN report only all year
DMP1pHINST MAX 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