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U.S. Fish & Wildlife Service, Patuxent Research Refuge

Federal facility (Sewerage Systems), Laurel, Maryland. NPDES permit MD0065358, in force until Jun 30, 2031. Last 12 months: no values over a limit, 42 required values missing, 12 of 24 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A monthly (21 values), outfall 101 form A monthly (21 values), outfall 101 form B yearly
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 136 required values missing, 16 of 24 reports late

Limits in force (46)

ParameterStatisticLimitMonthsOutfall
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/Lall year001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 30 mg/Lall year001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 45 mg/Lall year001
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 1.7 lb/dall year001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 2.5 lb/dall year001
pHminimum≥ 6.5 SUall year001
pHmaximum≤ 8.5 SUall year001
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year001
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year001
Solids, total suspendedmaximum monthly average≤ 1.7 lb/dall year001
Solids, total suspendedmaximum weekly average≤ 2.5 lb/dall year001
Nitrogen, ammonia total [as N]maximum monthly average≤ 12 mg/LMay–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ .67 lb/dMay–Oct001
Phosphorus, total [as P]maximum monthly average≤ .04 lb/dall year001
Phosphorus, total [as P]maximum weekly average≤ .06 lb/dall 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 residualmaximum≤ .037 mg/Lall year001
E. colimonthly averagereport only (MPN/100mL)all year001
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year001
Solids, suspended percent removalmonthly average minimum≥ 85 %all year001
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/Lall year101
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 30 mg/Lall year101
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 45 mg/Lall year101
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 1.7 lb/dall year101
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 2.5 lb/dall year101
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year101
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year101
pHminimum≥ 6.5 SUall year101
pHmaximum≤ 8.5 SUall year101
Solids, total suspendedmaximum monthly average≤ 30 mg/Lall year101
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year101
Solids, total suspendedmaximum monthly average≤ 1.7 lb/dall year101
Solids, total suspendedmaximum weekly average≤ 2.5 lb/dall year101
Solids, total suspendedmonthly averagereport only (mg/L)all year101
Solids, total suspendedmonthly averagereport only (mg/L)all year101
Nitrogen, ammonia total [as N]maximum monthly average≤ 12 mg/LMay–Oct101
Nitrogen, ammonia total [as N]maximum monthly average≤ .67 lb/dMay–Oct101
Phosphorus, total [as P]maximum monthly average≤ .04 lb/dall year101
Phosphorus, total [as P]maximum weekly average≤ .06 lb/dall year101
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year101
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year101
Chlorine, total residualmaximum≤ .037 mg/Lall year101
E. colimaximum monthly geometric mean≤ 126 MPN/100mLall year101
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year101
Solids, suspended percent removalmonthly average minimum≥ 85 %all year101

New limits from Jul 1, 2029

ParameterNew limitNew or tighterMedian, last 12 months× new limit
Nitrogen, ammonia total [as N], maximum monthly average outfall 0017.6 mg/L (May–Oct)tighter——
Nitrogen, ammonia total [as N], maximum monthly average outfall 0010.42 lb/d (May–Oct)tighter——
Nitrogen, ammonia total [as N], maximum monthly average outfall 1010.42 lb/d (May–Oct)tighter——
Nitrogen, ammonia total [as N], maximum monthly average outfall 1017.6 mg/L (May–Oct)tighter——

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/MD0065358 · MCP: https://passage-data.com/mcp