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City of Walterboro

Sewage treatment plant, major discharger, Walterboro, South Carolina. NPDES permit SC0040436 expired Sep 30, 2026; its limits still apply. Last 12 months: over a limit 3 times (last June 2026), 12 required values missing, 4 of 17 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 29 days after each period: form 1A monthly (61 values), form 2A quarterly, form 3A quarterly
Last report on file
August 2026
Oct 2024 – Sep 2025
6 values over a limit, 13 required values missing, 3 of 21 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
February 2026Nitrogen, ammonia total [as N], weekly average3.5≤ 3.26 mg/L7%
April 2026E. coli, daily maximum461≤ 349 MPN/100mL32%
June 2026E. coli, daily maximum365≤ 349 MPN/100mL5%

Limits in force (69)

ParameterStatisticLimitMonths
Oxygen demand, ultimatemonthly average= 451 lb/dall year
Oxygen demand, ultimateweekly average= 676.5 lb/dall year
Oxygen, dissolved [DO]minimum= 6 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average= 6.1 mg/Lall year
BOD, 5-day, 20 deg. Cweekly average= 9.15 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average= 286 lb/dall year
BOD, 5-day, 20 deg. Cweekly average= 429 lb/dall year
pHminimum= 6 SUall year
pHmaximum= 8.5 SUall year
Solids, total suspendedmonthly average= 30 mg/Lall year
Solids, total suspendedweekly average= 45 mg/Lall year
Solids, total suspendedmonthly average= 1407 lb/dall year
Solids, total suspendedweekly average= 2111 lb/dall year
Nitrogen, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, total [as N]weekly averagereport only (mg/L)all year
Nitrogen, total [as N]monthly averagereport only (lb/d)all year
Nitrogen, total [as N]weekly averagereport only (lb/d)all year
Nitrogen, ammonia total [as N]monthly average= 1.45 mg/Lall year
Nitrogen, ammonia total [as N]weekly average= 2.18 mg/Lall year
Nitrogen, ammonia total [as N]monthly average= 68 lb/dall year
Nitrogen, ammonia total [as N]weekly average= 102 lb/dall year
Phosphorus, total [as P]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]weekly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (lb/d)all year
Phosphorus, total [as P]weekly averagereport only (lb/d)all year
Cyanide, total [as CN]monthly average= .0053 mg/Lall year
Cyanide, total [as CN]daily maximum= .022 mg/Lall year
Cyanide, total [as CN]monthly average= .25 lb/dall year
Cyanide, total [as CN]daily maximum= 1.03 lb/dall year
Cadmium, total [as Cd]monthly averagereport only (mg/L)all year
Cadmium, total [as Cd]daily maximumreport only (mg/L)all year
Cadmium, total [as Cd]monthly averagereport only (lb/d)all year
Cadmium, total [as Cd]daily maximumreport only (lb/d)all year
Copper, total [as Cu]monthly average= .0098 mg/Lall year
Copper, total [as Cu]daily maximum= .013 mg/Lall year
Copper, total [as Cu]monthly average= .46 lb/dall year
Copper, total [as Cu]daily maximum= .61 lb/dall year
Lead, total [as Pb]monthly averagereport only (mg/L)all year
Lead, total [as Pb]daily maximumreport only (mg/L)all year
Lead, total [as Pb]monthly averagereport only (lb/d)all year
Lead, total [as Pb]daily maximumreport only (lb/d)all year
Zinc, total [as Zn]monthly averagereport only (mg/L)all year
Zinc, total [as Zn]daily maximumreport only (mg/L)all year
Zinc, total [as Zn]monthly averagereport only (lb/d)all year
Zinc, total [as Zn]daily maximumreport only (lb/d)all year
Di[2-ethylhexyl] phthalate [DEHP]monthly average= .019 mg/Lall year
Di[2-ethylhexyl] phthalate [DEHP]daily maximum= .028 mg/Lall year
Di[2-ethylhexyl] phthalate [DEHP]monthly average= .89 lb/dall year
Di[2-ethylhexyl] phthalate [DEHP]daily maximum= 1.31 lb/dall year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantweekly averagereport only (MGD)all year
Chlorine, total residualmonthly average= .011 mg/Lall year
Chlorine, total residualdaily maximum= .019 mg/Lall year
Chlorine, total residualmonthly average= .51 lb/dall year
Chlorine, total residualdaily maximum= .89 lb/dall year
E. coli30-day geometric mean= 126 MPN/100mLall year
E. colidaily maximum= 400 MPN/100mLall year
E. coli30-day geometric mean= 126 MPN/100mLall year
E. colidaily maximum= 800 MPN/100mLall year
Mercury, total [as Hg]monthly average≤ 51 ng/Lall year
Mercury, total [as Hg]daily maximum≤ 74 ng/Lall year
Mercury, total [as Hg]monthly average≤ .0024 lb/dall year
Mercury, total [as Hg]daily maximum≤ .0035 lb/dall year
BOD, 5-day, percent removalmonthly average minimum= 85 %all year
Solids, suspended percent removalmonthly average minimum= 85 %all year
LC50 Static 48Hr Acute Ceriodaphnia dubiadaily minimumreport only (%)all year
%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiamonthly average= 25 %all year
%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiadaily maximum= 40 %all year
IC25 Static Renewal 7 Day Chronic Ceriodaphnia dubiadaily minimumreport only (%)all year

Cited limits by parameter: South Carolina's rules and the federal ones.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/SC0040436 · MCP: https://passage-data.com/mcp