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Lowcountry Regional Water System

Sewage treatment plant, Yemassee, South Carolina. NPDES permit SC0025950 expired Mar 31, 2021; its limits still apply. Last 12 months: over a limit 14 times (last July 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 29 days after each period: form 1 monthly (37 values), form 2 yearly, form 3 yearly
Last report on file
September 2026
Oct 2024 – Sep 2025
17 values over a limit, 0 required values missing, 0 of 14 reports late

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

All 14 values over a limit
Period endingParameterReportedLimitOver by
January 2026Nitrogen, ammonia total [as N], monthly average20.5≤ 15 mg/L37%
January 2026Nitrogen, ammonia total [as N], weekly average24≤ 22.5 mg/L7%
February 2026BOD, carbonaceous [5 day, 20 C], monthly average26≤ 25 mg/L4%
February 2026Nitrogen, ammonia total [as N], monthly average17≤ 15 mg/L13%
February 2026Nitrogen, ammonia total [as N], weekly average25≤ 22.5 mg/L11%
March 2026E. coli, daily maximum980.4≤ 349 MPN/100mL181%
May 2026Nitrogen, ammonia total [as N], monthly average20.5≤ 15 mg/L37%
May 2026Nitrogen, ammonia total [as N], weekly average24≤ 22.5 mg/L7%
June 2026Nitrogen, ammonia total [as N], monthly average19≤ 15 mg/L27%
July 2026BOD, carbonaceous [5 day, 20 C], monthly average26.07≤ 25 mg/L4%
July 2026BOD, carbonaceous [5 day, 20 C], weekly average63≤ 37.5 mg/L68%
July 2026Nitrogen, ammonia total [as N], monthly average26.33≤ 15 mg/L76%
July 2026Nitrogen, ammonia total [as N], weekly average31≤ 22.5 mg/L38%
July 2026Oxygen demand, ultimate, weekly average299.78≤ 232.6 lb/d29%

Limits in force (45)

ParameterStatisticLimitMonths
Oxygen demand, ultimatemonthly average≤ 416 lb/dJan, Feb, Nov, Dec
Oxygen demand, ultimatemonthly average≤ 232.6 lb/dMar–Oct
Oxygen demand, ultimateweekly average≤ 416 lb/dJan, Feb, Nov, Dec
Oxygen demand, ultimateweekly average≤ 232.6 lb/dMar–Oct
Oxygen, dissolved [DO]minimum≥ 5 mg/Lall year
pHminimum≥ 6 SUall year
pHmaximum≤ 8.5 SUall year
Solids, total suspendedmonthly average≤ 90 mg/Lall year
Solids, total suspendedweekly average≤ 135 mg/Lall year
Solids, total suspendedmonthly average≤ 375 lb/dall year
Solids, total suspendedweekly average≤ 563 lb/dall year
Nitrogen, ammonia total [as N]monthly average≤ 15 mg/Lall year
Nitrogen, ammonia total [as N]weekly average≤ 22.5 mg/Lall year
Nitrogen, ammonia total [as N]monthly average≤ 63 lb/dall year
Nitrogen, ammonia total [as N]weekly average≤ 95 lb/dall year
Nitrogen, nitrate total [as N]monthly averagereport only (mg/L)all year
Nitrogen, nitrate total [as N]weekly averagereport only (mg/L)all year
Nitrogen, nitrate total [as N]monthly averagereport only (lb/d)all year
Nitrogen, nitrate total [as N]weekly averagereport only (lb/d)all 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
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≤ .5 mg/Lall year
Chlorine, total residualdaily maximum≤ .928 mg/Lall year
Chlorine, total residualmonthly average≤ 2.09 lb/dall year
Chlorine, total residualdaily maximum≤ 3.87 lb/dall year
E. coli30-day geometric mean≤ 126 MPN/100mLall year
E. colidaily maximum≤ 349 MPN/100mLall year
E. coli30-day geometric mean≤ 126 MPN/100mLall year
E. colidaily maximum≤ 800 MPN/100mLall year
Mercury, total [as Hg]monthly averagereport only (mg/L)all year
Mercury, total [as Hg]daily maximumreport only (mg/L)all year
Mercury, total [as Hg]monthly averagereport only (lb/d)all year
Mercury, total [as Hg]daily maximumreport only (lb/d)all year
BOD, carbonaceous [5 day, 20 C]monthly average≤ 25 mg/Lall year
BOD, carbonaceous [5 day, 20 C]weekly average≤ 37.5 mg/Lall year
BOD, carbonaceous [5 day, 20 C]monthly average≤ 104 lb/dall year
BOD, carbonaceous [5 day, 20 C]weekly average≤ 156 lb/dall year
Solids, suspended percent removalmonthly average minimum≥ 65 %all year
Carbonaceous oxygen demand, % removalmonthly average minimum≥ 85 %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

How strict are these limits?

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/SC0025950 · MCP: https://passage-data.com/mcp