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South Island Public Service District

Sewage treatment plant, major discharger, Hilton Head Island, South Carolina. NPDES permit SC0042501, in force until Jan 31, 2029. 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 (41 values), form 2 yearly
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 41 required values missing, 0 of 13 reports late

Limits in force (45)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]minimum≥ 5 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 8.9 mg/Lall year
BOD, 5-day, 20 deg. Cweekly average≤ 13.4 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 371 lb/dall year
BOD, 5-day, 20 deg. Cweekly average≤ 557 lb/dall year
pHminimum≥ 6 SUall year
pHmaximum≤ 8.5 SUall year
Solids, total suspendedmonthly average≤ 8.9 mg/Lall year
Solids, total suspendedweekly average≤ 13.4 mg/Lall year
Solids, total suspendedmonthly average≤ 371 lb/dall year
Solids, total suspendedweekly average≤ 557 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≤ 3.3 mg/Lall year
Nitrogen, ammonia total [as N]weekly average≤ 5 mg/Lall year
Nitrogen, ammonia total [as N]monthly average≤ 138 lb/dall year
Nitrogen, ammonia total [as N]weekly average≤ 207 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
Hardness, total [as CaCO3]monthly averagereport only (mg/L)all year
Hardness, total [as CaCO3]daily maximumreport only (mg/L)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≤ .008 mg/Lall year
Chlorine, total residualdaily maximum≤ .013 mg/Lall year
Chlorine, total residualmonthly average≤ .33 lb/dall year
Chlorine, total residualdaily maximum≤ .54 lb/dall year
Enterococcimonthly average≤ 35 MPN/100mLall year
Enterococcidaily maximum≤ 104 MPN/100mLall year
Enterococcimonthly average≤ 35 MPN/100mLall year
Enterococcidaily maximum≤ 800 MPN/100mLall year
Coliform, fecal generalmonthly average≤ 14 MPN/100mLall year
Coliform, fecal generaldaily maximum≤ 43 MPN/100mLall year
Coliform, fecal general30-day geometric mean≤ 14 MPN/100mLall year
Coliform, fecal generaldaily maximum≤ 200 MPN/100mLall 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

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/SC0042501 · MCP: https://passage-data.com/mcp