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Trappe WWTP

Sewage treatment plant, Trappe, Maryland. NPDES permit MD0020486 expired Aug 31, 2024; its limits still apply. Last 12 months: over a limit 7 times (last August 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 29 days after each period: form A monthly (32 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 19 required values missing, 5 of 12 reports late

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

Period endingParameterReportedLimitOver by
October 2025Phosphorus, total [as P], maximum weekly average1 mg/L≤ .45 mg/L122%
November 2025Phosphorus, total [as P], maximum monthly average.85 mg/L≤ .3 mg/L183%
November 2025Phosphorus, total [as P], maximum weekly average1.35 mg/L≤ .45 mg/L200%
February 2026pH, maximum9.7 SU≤ 8.5 SU—
March 2026Phosphorus, total [as P], maximum weekly average.47 mg/L≤ .45 mg/L4%
April 2026Phosphorus, total [as P], maximum weekly average.46 mg/L≤ .45 mg/L2%
August 2026Phosphorus, total [as P], maximum weekly average.56 mg/L≤ .45 mg/L24%

Limits in force (40)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]instantaneous minimum≥ 6 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 10 mg/LMay–Sep
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 30 mg/LJan, Feb, Mar, Apr, Oct, Nov, Dec
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 15 mg/LMay–Sep
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 45 mg/LJan, Feb, Mar, Apr, Oct, Nov, Dec
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 17 lb/dMay–Sep
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 50 lb/dJan, Feb, Mar, Apr, Oct, Nov, Dec
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 25 lb/dMay–Sep
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 75 lb/dJan, Feb, Mar, Apr, Oct, Nov, Dec
pHminimum≥ 6.5 SUall year
pHmaximum≤ 8.5 SUall year
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year
Solids, total suspendedmaximum monthly average≤ 50 lb/dall year
Solids, total suspendedmaximum weekly average≤ 75 lb/dall year
Nitrogen, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, total [as N]monthly totalreport only (lb/mo)all year
Nitrogen, total [as N]annual maximumreport only (lb/yr)all year
Nitrogen, organic total [as N]monthly averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]maximum monthly average≤ 1.3 mg/LMay–Sep
Nitrogen, ammonia total [as N]maximum monthly average≤ 2.7 mg/LJan, Feb, Mar, Apr, Oct, Nov, Dec
Nitrogen, ammonia total [as N]maximum daily average≤ 10.1 mg/LMay–Sep
Nitrogen, ammonia total [as N]maximum daily average≤ 10.1 mg/LJan, Feb, Mar, Apr, Oct, Nov, Dec
Nitrogen, ammonia total [as N]maximum monthly average≤ 2.2 lb/dMay–Sep
Nitrogen, ammonia total [as N]maximum monthly average≤ 4.5 lb/dJan, Feb, Mar, Apr, Oct, Nov, Dec
Nitrogen, ammonia total [as N]maximum daily average≤ 16.8 lb/dMay–Sep
Nitrogen, ammonia total [as N]maximum daily average≤ 16.8 lb/dJan, Feb, Mar, Apr, Oct, Nov, Dec
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]maximum monthly average≤ .3 mg/Lall year
Phosphorus, total [as P]maximum weekly average≤ .45 mg/Lall year
Phosphorus, total [as P]maximum monthly average≤ .5 lb/dall year
Phosphorus, total [as P]monthly totalreport only (lb/mo)all year
Phosphorus, total [as P]maximum weekly average≤ .75 lb/dall year
Phosphorus, total [as P]annual maximum≤ 183 lb/yrall year
Phosphate, ortho [as P]monthly averagereport only (mg/L)all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year
Chlorine, total residualmaximum≤ .1 mg/Lall year
Coliform, fecal generalmonthly median≤ 14 MPN/100mLall year
Flow, totalmonthly totalreport only (Mgal/mo)all year

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/MD0020486 · MCP: https://passage-data.com/mcp