CHARLESTON WATER SYSTEM

NPDES permit SC0047074 · Minor POTW · effective, expires 2031-04-30 · 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

0values over a limit
0required values missing, on 0 form(s)
0of 15 forms filed late

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

Reporting

Reports are due about 29 days after each monitoring period ends (the most common figure among SC permits in EPA's filings — check your permit).

Limits in force (35)

OutfallParameterStatisticLimitMonths
001Oxygen, dissolved [DO]MINIMUM >= 5 mg/L all year
001pHMINIMUM >= 6 SU all year
001pHMAXIMUM <= 8.5 SU all year
001Solids, total suspendedMO AVG <= 30 mg/L all year
001Solids, total suspendedWKLY AVG <= 45 mg/L all year
001Solids, total suspendedMO AVG <= 225 lb/d all year
001Solids, total suspendedWKLY AVG <= 338 lb/d all year
001Nitrogen, ammonia total [as N]MO AVG <= 1.08 mg/L Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 2.59 mg/L Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY AVG <= 1.62 mg/L Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY AVG <= 3.89 mg/L Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]MO AVG <= 8 lb/d Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 19 lb/d Jan, Feb, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY AVG <= 12 lb/d Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY AVG <= 29 lb/d Jan, Feb, Nov, Dec
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantWKLY AVG report only all year
001Chlorine, total residualMO AVG <= .008 mg/L all year
001Chlorine, total residualDAILY MX <= .013 mg/L all year
001Chlorine, total residualMO AVG <= .06 lb/d all year
001Chlorine, total residualDAILY MX <= .1 lb/d all year
001Enterococci30DAVGEO <= 35 MPN/100mL all year
001EnterococciDAILY MX <= 104 MPN/100mL all year
001Enterococci30DAVGEO <= 35 MPN/100mL all year
001EnterococciDAILY MX <= 800 MPN/100mL all year
001BOD, carbonaceous [5 day, 20 C]MO AVG <= 5 mg/L all year
001BOD, carbonaceous [5 day, 20 C]WKLY AVG <= 7.5 mg/L all year
001BOD, carbonaceous [5 day, 20 C]MO AVG <= 38 lb/d all year
001BOD, carbonaceous [5 day, 20 C]WKLY AVG <= 57 lb/d all year
001Solids, suspended percent removalMO AV MN >= 85 % all year
001Carbonaceous oxygen demand, % removalMO AV MN >= 85 % all year
001LC50 Static 48Hr Acute Americamysis bahia (formerly Mysidopsis bahia)DAILY MN report only all year
001% Effect Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)MO AVG <= 25 % all year
001% Effect Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)DAILY MX <= 40 % all year
001IC25 Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)DAILY 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