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Preston WWTP

Sewage treatment plant, Preston (Co--0525), Maryland. NPDES permit MD0020621, in force until Jan 31, 2030. Last 12 months: over a limit 5 times (last February 2026), 2 of 23 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form EN monthly (34 values), outfall 101 form A monthly (2 values), outfall 001 form B yearly
Last report on file
August 2026
Oct 2024 – Sep 2025
5 values over a limit, 2 required values missing, 1 of 20 reports late

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

Period endingParameterReportedLimitOver by
December 2025BOD, 5-day, 20 deg. C, maximum weekly average54 mg/L≤ 45 mg/L20%
January 2026BOD, 5-day, 20 deg. C, maximum monthly average40.65 mg/L≤ 30 mg/L36%
January 2026BOD, 5-day, 20 deg. C, maximum weekly average47.8 mg/L≤ 45 mg/L6%
January 2026Solids, total suspended, maximum weekly average56 mg/L≤ 45 mg/L24%
February 2026BOD, 5-day, 20 deg. C, maximum monthly average34.73 mg/L≤ 30 mg/L16%

Limits in force (46)

ParameterStatisticLimitMonthsOutfall
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/Lall year001
Oxygen, dissolved [DO]minimum weekly average≥ 6 mg/LFeb–May001
Oxygen, dissolved [DO]monthly average minimum≥ 5.5 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≤ 29 lb/dall year001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 43 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≤ 29 lb/dall year001
Solids, total suspendedmaximum weekly average≤ 43 lb/dall year001
Solids, total suspendedmonthly totalreport only (lb/mo)all year001
Solids, total suspendedcumulative total≤ 10598 lb/yrall year001
Nitrogen, total [as N]monthly averagereport only (mg/L)all year001
Nitrogen, total [as N]monthly totalreport only (lb/mo)all year001
Nitrogen, total [as N]cumulative total≤ 1400 lb/yrall year001
Nitrogen, total [as N]annual totalreport only (lb/yr)all year001
Nitrogen, total [as N]annual totalreport only (lb/yr)all year001
Nitrogen, organic total [as N]monthly averagereport only (mg/L)all year001
Nitrogen, ammonia total [as N]maximum monthly average≤ 1.9 mg/LMay–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ 8.4 mg/LJan, Feb, Mar, Apr, Nov, Dec001
Nitrogen, ammonia total [as N]maximum daily average≤ 6.3 mg/LMay–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ 1.8 lb/dMay–Oct001
Nitrogen, ammonia total [as N]maximum monthly average≤ 8.1 lb/dJan, Feb, Mar, Apr, Nov, Dec001
Nitrogen, ammonia total [as N]maximum daily average≤ 6 lb/dMay–Oct001
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]cumulative total≤ 105 lb/yrall year001
Phosphorus, total [as P]monthly totalreport only (lb/mo)all year001
Phosphorus, total [as P]annual totalreport only (lb/yr)all year001
Phosphorus, total [as P]annual totalreport only (lb/yr)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 residualmaximum≤ .032 mg/Lall year001
E. colimaximum monthly geometric mean< 126 MPN/100mLall year001
Phosphorous, in total orthophosphatemonthly averagereport only (mg/L)all year001
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year001
Solids, suspended percent removalmonthly average minimum≥ 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
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year101
Solids, total suspendedmonthly averagereport only (mg/L)all year101

How strict are these limits?

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

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

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MD0020621 · MCP: https://passage-data.com/mcp