Passage Data · Check a report · Use it from your AI

Charleston Water System

Sewage treatment plant, Charleston, South Carolina. NPDES permit SC0047074, in force until Apr 30, 2031. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 29 days after each period: form 1 monthly (27 values), form 2 quarterly
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 16 reports late

Limits in force (35)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]minimum≥ 5 mg/Lall 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≤ 225 lb/dall year
Solids, total suspendedweekly average≤ 338 lb/dall year
Nitrogen, ammonia total [as N]monthly average≤ 1.08 mg/LMar–Oct
Nitrogen, ammonia total [as N]monthly average≤ 2.59 mg/LJan, Feb, Nov, Dec
Nitrogen, ammonia total [as N]weekly average≤ 1.62 mg/LMar–Oct
Nitrogen, ammonia total [as N]weekly average≤ 3.89 mg/LJan, Feb, Nov, Dec
Nitrogen, ammonia total [as N]monthly average≤ 8 lb/dMar–Oct
Nitrogen, ammonia total [as N]monthly average≤ 19 lb/dJan, Feb, Nov, Dec
Nitrogen, ammonia total [as N]weekly average≤ 12 lb/dMar–Oct
Nitrogen, ammonia total [as N]weekly average≤ 29 lb/dJan, Feb, Nov, Dec
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≤ .008 mg/Lall year
Chlorine, total residualdaily maximum≤ .013 mg/Lall year
Chlorine, total residualmonthly average≤ .06 lb/dall year
Chlorine, total residualdaily maximum≤ .1 lb/dall year
Enterococci30-day geometric mean≤ 35 MPN/100mLall year
Enterococcidaily maximum≤ 104 MPN/100mLall year
Enterococci30-day geometric mean≤ 35 MPN/100mLall year
Enterococcidaily maximum≤ 800 MPN/100mLall year
BOD, carbonaceous [5 day, 20 C]monthly average≤ 5 mg/Lall year
BOD, carbonaceous [5 day, 20 C]weekly average≤ 7.5 mg/Lall year
BOD, carbonaceous [5 day, 20 C]monthly average≤ 38 lb/dall year
BOD, carbonaceous [5 day, 20 C]weekly average≤ 57 lb/dall year
Solids, suspended percent removalmonthly average minimum≥ 85 %all year
Carbonaceous oxygen demand, % removalmonthly average minimum≥ 85 %all year
LC50 Static 48Hr Acute Americamysis bahia (formerly Mysidopsis bahia)daily minimumreport only (%)all year
% Effect Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)monthly average≤ 25 %all year
% Effect Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)daily maximum≤ 40 %all year
IC25 Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)daily minimumreport only (%)all year

How strict are these limits?

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

Check this month's numbers Email me before each report is due

· Save this facility as a site · Superfund sites nearby · Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/SC0047074 · MCP: https://passage-data.com/mcp