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Washington Suburban Sanitary Commission - WSSC

Sewage treatment plant, major discharger, Upper Marlboro, Maryland. NPDES permit MD0021741, in force until Mar 31, 2028. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A monthly (43 values), outfall TRAD form E monthly (7 values), outfall 001 form B yearly
Renewal application due
Oct 3, 2027 · 180 days before expiry; your permit may set another date
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 25 reports late

Limits in force (70)

ParameterStatisticLimitMonthsOutfall
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/LFeb–May001
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/LJan, Jun, Jul, Aug, Sep, Oct, Nov, Dec001
Oxygen, dissolved [DO]monthly average minimum≥ 5.5 mg/LFeb–May001
Oxygen, dissolved [DO]monthly average minimum≥ 5.5 mg/LJan, Jun, Jul, Aug, Sep, Oct, Nov, Dec001
Oxygen, dissolved [DO]minimum weekly average≥ 6 mg/LFeb–May001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 9 mg/LApr–Oct001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 30 mg/LJan, Feb, Mar, Nov, Dec001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 14 mg/LApr–Oct001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 45 mg/LJan, Feb, Mar, Nov, Dec001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 2300 lb/dApr–Oct001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 7500 lb/dJan, Feb, Mar, Nov, Dec001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 3500 lb/dApr–Oct001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 11300 lb/dJan, Feb, Mar, Nov, Dec001
pHminimum≥ 6.5 SUall year001
pHmaximum≤ 8.5 SUall year001
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year001
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year001
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year001
Solids, total suspendedmaximum monthly average≤ 7500 lb/dall year001
Solids, total suspendedmaximum weekly average≤ 11300 lb/dall year001
Solids, total suspendedannual maximum≤ 2737500 lb/yrall year001
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year001
Solids, total suspendedmonthly totalreport only (lb/mo)all year001
Nitrogen, total [as N]maximum monthly average≤ 3 mg/LApr–Oct001
Nitrogen, total [as N]maximum weekly average≤ 4.5 mg/LApr–Oct001
Nitrogen, total [as N]maximum monthly average≤ 770 lb/dApr–Oct001
Nitrogen, total [as N]monthly totalreport only (lb/mo)all year001
Nitrogen, total [as N]maximum weekly average≤ 1150 lb/dApr–Oct001
Nitrogen, total [as N]cumulative total≤ 372776 lb/yrall year001
Nitrogen, total [as N]annual totalreport only (lb/yr)Dec001
Nitrogen, total [as N]annual totalreport only (lb/yr)all year001
Nitrogen, total [as N]annual totalreport only (lb/yr)all year001
Nitrogen, total [as N]monthly averagereport only (mg/L)Jan, Feb, Mar, Nov, Dec001
Nitrogen, total [as N]monthly averagereport only (lb/d)Jan, Feb, Mar, Nov, Dec001
Nitrogen, organic total [as N]monthly averagereport only (mg/L)all year001
Nitrogen, ammonia total [as N]maximum monthly average≤ 1.5 mg/LApr–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ 4.4 mg/LJan, Feb, Mar, Nov, Dec001
Nitrogen, ammonia total [as N]maximum monthly average≤ 383 lb/dApr–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ 1124 lb/dJan, Feb, Mar, Nov, Dec001
Nitrogen, Kjeldahl, total [as N]monthly averagereport only (mg/L)all year001
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]maximum monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]maximum monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]monthly totalreport only (lb/mo)all year001
Phosphorus, total [as P]annual maximum≤ 2737500 lb/yrall year001
Phosphorus, total [as P]annual totalreport only (lb/yr)Dec001
Phosphorus, total [as P]annual totalreport only (lb/yr)all year001
Phosphorus, total [as P]annual totalreport only (lb/yr)all year001
Hardness, total [as CaCO3]monthly averagereport only (mg/L)all year001
Hardness, total [as CaCO3]monthly averagereport only (mg/L)all year001
Copper, total recoverablemonthly averagereport only (ug/L)all year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year001
Chlorine, total residualdaily maximum≤ .1 mg/Lall year001
Enterococcimaximum≤ 35 MPN/100mLall year001
Phosphorous, in total orthophosphatemonthly averagereport only (mg/L)all year001
Phosphorous, in total orthophosphatemonthly loadreport only (lb/d)all year001
BOD, 5-day, percent removalminimum≥ 85 %all year001
Solids, suspended percent removalminimum≥ 85 %all year001
Flow, totalannual totalreport only (Mgal/yr)Dec001
Flow, totalmonthly totalreport only (Mgal/mo)all year001
Flow, totalannual totalreport only (Mgal/yr)all year001
Flow, totalannual totalreport only (Mgal/yr)all year001
Solids, total suspendedcumulative totalreport only (lb/yr)all yearTRAD
Solids, total suspendedcumulative totalreport only (lb/yr)all yearTRAD
Nitrogen, total [as N]cumulative totalreport only (lb/yr)all yearTRAD
Nitrogen, total [as N]cumulative totalreport only (lb/yr)all yearTRAD
Phosphorus, total [as P]cumulative totalreport only (lb/yr)all yearTRAD
Phosphorus, total [as P]cumulative totalreport only (lb/yr)all yearTRAD
Flowyear-to-date totalreport only (Mgal/yr)all yearTRAD

How strict are these limits?

Cited limits by parameter: Maryland'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/MD0021741 · MCP: https://passage-data.com/mcp