City of Walterboro

NPDES permit SC0040436 · Major POTW · effective, expires 2026-09-30 · 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

4values over a limit
16required values missing, on 4 form(s)
5of 20 forms filed late

Last period with anything received: 2026-07-31. Most often over: E. coli (3), Nitrogen, ammonia total [as N] (1).

Reporting

Reports are due about 29 days after each monitoring period ends (read off this permit's own late-day counts in EPA's filings).

Limits in force (118)

OutfallParameterStatisticLimitMonths
001Oxygen demand, ultimateMO AVG = 451 lb/d all year
001Oxygen demand, ultimateMO AVG <= 451 lb/d all year
001Oxygen demand, ultimateWKLY AVG = 676.5 lb/d all year
001Oxygen demand, ultimateWKLY AVG <= 676.5 lb/d all year
001Oxygen, dissolved [DO]MINIMUM = 6 mg/L all year
001Oxygen, dissolved [DO]MINIMUM >= 6 mg/L all year
001BOD, 5-day, 20 deg. CMO AVG = 6.1 mg/L all year
001BOD, 5-day, 20 deg. CMO AVG <= 10 mg/L all year
001BOD, 5-day, 20 deg. CWKLY AVG = 9.15 mg/L all year
001BOD, 5-day, 20 deg. CWKLY AVG <= 15 mg/L all year
001BOD, 5-day, 20 deg. CMO AVG = 286 lb/d all year
001BOD, 5-day, 20 deg. CMO AVG <= 220 lb/d all year
001BOD, 5-day, 20 deg. CWKLY AVG = 429 lb/d all year
001BOD, 5-day, 20 deg. CWKLY AVG <= 330 lb/d all year
001pHMINIMUM = 6 SU all year
001pHMINIMUM >= 6 SU all year
001pHMAXIMUM = 8.5 SU all year
001pHMAXIMUM <= 8.5 SU all year
001Solids, total suspendedMO AVG <= 30 mg/L all year
001Solids, total suspendedMO AVG = 30 mg/L all year
001Solids, total suspendedWKLY AVG <= 45 mg/L all year
001Solids, total suspendedWKLY AVG = 45 mg/L all year
001Solids, total suspendedMO AVG <= 661 lb/d all year
001Solids, total suspendedMO AVG = 1407 lb/d all year
001Solids, total suspendedWKLY AVG <= 991 lb/d all year
001Solids, total suspendedWKLY AVG = 2111 lb/d all year
001Nitrogen, total [as N]MO AVG report only all year
001Nitrogen, total [as N]MO AVG report only all year
001Nitrogen, total [as N]WKLY AVG report only all year
001Nitrogen, total [as N]WKLY AVG report only all year
001Nitrogen, total [as N]MO AVG report only all year
001Nitrogen, total [as N]MO AVG report only all year
001Nitrogen, total [as N]WKLY AVG report only all year
001Nitrogen, total [as N]WKLY AVG report only all year
001Nitrogen, ammonia total [as N]MO AVG = 1.45 mg/L all year
001Nitrogen, ammonia total [as N]MO AVG <= 2 mg/L Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 2.17 mg/L Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY AVG = 2.18 mg/L all year
001Nitrogen, ammonia total [as N]WKLY AVG <= 3 mg/L Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY AVG <= 3.26 mg/L Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]MO AVG = 68 lb/d all year
001Nitrogen, ammonia total [as N]MO AVG <= 44 lb/d Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 48 lb/d Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY AVG = 102 lb/d all year
001Nitrogen, ammonia total [as N]WKLY AVG <= 66 lb/d Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY AVG <= 72 lb/d Jan, Feb, Nov, Dec
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]WKLY AVG report only all year
001Phosphorus, total [as P]WKLY AVG report only all year
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]WKLY AVG report only all year
001Phosphorus, total [as P]WKLY AVG report only all year
001Cyanide, total [as CN]MO AVG = .0053 mg/L all year
001Cyanide, total [as CN]DAILY MX = .022 mg/L all year
001Cyanide, total [as CN]MO AVG = .25 lb/d all year
001Cyanide, total [as CN]DAILY MX = 1.03 lb/d all year
001Cadmium, total [as Cd]MO AVG report only all year
001Cadmium, total [as Cd]DAILY MX report only all year
001Cadmium, total [as Cd]MO AVG report only all year
001Cadmium, total [as Cd]DAILY MX report only all year
001Copper, total [as Cu]MO AVG = .0098 mg/L all year
001Copper, total [as Cu]DAILY MX = .013 mg/L all year
001Copper, total [as Cu]MO AVG = .46 lb/d all year
001Copper, total [as Cu]DAILY MX = .61 lb/d all year
001Lead, total [as Pb]MO AVG report only all year
001Lead, total [as Pb]DAILY MX report only all year
001Lead, total [as Pb]MO AVG report only all year
001Lead, total [as Pb]DAILY MX report only all year
001Zinc, total [as Zn]MO AVG report only all year
001Zinc, total [as Zn]DAILY MX report only all year
001Zinc, total [as Zn]MO AVG report only all year
001Zinc, total [as Zn]DAILY MX report only all year
001Di[2-ethylhexyl] phthalate [DEHP]MO AVG = .019 mg/L all year
001Di[2-ethylhexyl] phthalate [DEHP]DAILY MX = .028 mg/L all year
001Di[2-ethylhexyl] phthalate [DEHP]MO AVG = .89 lb/d all year
001Di[2-ethylhexyl] phthalate [DEHP]DAILY MX = 1.31 lb/d all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantWKLY AVG report only all year
001Flow, in conduit or thru treatment plantWKLY AVG report only all year
001Chlorine, total residualMO AVG <= .011 mg/L all year
001Chlorine, total residualMO AVG = .011 mg/L all year
001Chlorine, total residualDAILY MX <= .02 mg/L all year
001Chlorine, total residualDAILY MX = .019 mg/L all year
001Chlorine, total residualMO AVG <= .24 lb/d all year
001Chlorine, total residualMO AVG = .51 lb/d all year
001Chlorine, total residualDAILY MX <= .44 lb/d all year
001Chlorine, total residualDAILY MX = .89 lb/d all year
001E. coli30DAVGEO = 126 MPN/100mL all year
001E. coli30DAVGEO <= 126 MPN/100mL all year
001E. coliDAILY MX = 400 MPN/100mL all year
001E. coliDAILY MX <= 349 MPN/100mL all year
001E. coli30DAVGEO = 126 MPN/100mL all year
001E. coli30DAVGEO <= 126 MPN/100mL all year
001E. coliDAILY MX = 800 MPN/100mL all year
001E. coliDAILY MX <= 800 MPN/100mL all year
001Mercury, total [as Hg]MO AVG = 51 ng/L all year
001Mercury, total [as Hg]MO AVG <= 51 ng/L all year
001Mercury, total [as Hg]DAILY MX = 74 ng/L all year
001Mercury, total [as Hg]DAILY MX <= 87 ng/L all year
001Mercury, total [as Hg]MO AVG = .0024 lb/d all year
001Mercury, total [as Hg]MO AVG <= .0011 lb/d all year
001Mercury, total [as Hg]DAILY MX = .0035 lb/d all year
001Mercury, total [as Hg]DAILY MX <= .0019 lb/d all year
001BOD, 5-day, percent removalMO AV MN >= 85 % all year
001BOD, 5-day, percent removalMO AV MN = 85 % all year
001Solids, suspended percent removalMO AV MN >= 85 % all year
001Solids, suspended percent removalMO AV MN = 85 % all year
001LC50 Static 48Hr Acute Ceriodaphnia dubiaDAILY MN report only all year
001LC50 Static 48Hr Acute Ceriodaphnia dubiaDAILY MN report only all year
001%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaMO AVG <= 25 % all year
001%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaMO AVG = 25 % all year
001%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaDAILY MX <= 40 % all year
001%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaDAILY MX = 40 % all year
001IC25 Static Renewal 7 Day Chronic Ceriodaphnia dubiaDAILY MN report only all year
001IC25 Static Renewal 7 Day Chronic Ceriodaphnia dubiaDAILY MN 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