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Westtown TWP Chester Cnty

Sewage treatment plant, West Chester, Pennsylvania. NPDES permit PA0031771, in force until Mar 31, 2031. Last 12 months: over a limit 3 times (last June 2026), 32 required values missing. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form A monthly (32 values), form Q quarterly
Last report on file
June 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 16 reports late

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

Period endingParameterReportedLimitOver by
May 2026Solids, total suspended, weekly average54 mg/L≤ 45 mg/L20%
June 2026Phosphorus, total [as P], monthly average1.1 mg/L≤ 1 mg/L10%
June 2026Solids, total suspended, weekly average49 mg/L≤ 45 mg/L9%

Limits in force (44)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]instantaneous minimum≥ 5 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmonthly averagereport only (lb/d)all year
pHinstantaneous minimum≥ 6 SUall year
pHinstantaneous maximum≤ 9 SUall year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendedweekly average≤ 45 mg/Lall year
Solids, total suspendedmonthly average≤ 124 lb/dall year
Solids, total suspendedweekly average≤ 186 lb/dall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendedmonthly averagereport only (lb/d)all year
Nitrogen, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, total [as N]monthly averagereport only (lb/d)all year
Nitrogen, ammonia total [as N]monthly average≤ 2.5 mg/LMay–Oct
Nitrogen, ammonia total [as N]monthly average≤ 7.5 mg/LJan, Feb, Mar, Apr, Nov, Dec
Nitrogen, ammonia total [as N]monthly average≤ 10 lb/dMay–Oct
Nitrogen, ammonia total [as N]monthly average≤ 31 lb/dJan, Feb, Mar, Apr, Nov, Dec
Phosphorus, total [as P]monthly average≤ 1 mg/LMay–Oct
Phosphorus, total [as P]monthly average≤ 2 mg/LJan, Feb, Mar, Apr, Nov, Dec
Phosphorus, total [as P]monthly average≤ 4.1 lb/dMay–Oct
Phosphorus, total [as P]monthly average≤ 8.2 lb/dJan, Feb, Mar, Apr, Nov, Dec
Copper, total [as Cu]monthly average≤ .028 mg/Lall year
Copper, total [as Cu]daily maximum≤ .056 mg/Lall year
Copper, total [as Cu]monthly average≤ .12 lb/dall year
Copper, total [as Cu]daily maximum≤ .23 lb/dall year
Ultraviolet light intensitydaily minimumreport only (uW/cm2)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
Solids, total dissolveddaily maximumreport only (mg/L)all year
Solids, total dissolveddaily maximumreport only (lb/d)all year
Coliform, fecal generalgeometric mean≤ 200 #/100mLMay–Sep
Coliform, fecal generalgeometric mean≤ 200 #/100mLJan, Feb, Mar, Apr, Oct, Nov, Dec
Coliform, fecal generalinstantaneous maximum≤ 1000 #/100mLMay–Sep
Coliform, fecal generalinstantaneous maximum≤ 1000 #/100mLJan, Feb, Mar, Apr, Oct, Nov, Dec
BOD, carbonaceous [5 day, 20 C]monthly average≤ 15 mg/LMay–Oct
BOD, carbonaceous [5 day, 20 C]monthly average≤ 25 mg/LJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]weekly average≤ 23 mg/LMay–Oct
BOD, carbonaceous [5 day, 20 C]weekly average≤ 40 mg/LJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]monthly average≤ 62 lb/dMay–Oct
BOD, carbonaceous [5 day, 20 C]monthly average≤ 103 lb/dJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]weekly average≤ 95 lb/dMay–Oct
BOD, carbonaceous [5 day, 20 C]weekly average≤ 165 lb/dJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]monthly averagereport only (mg/L)all year
BOD, carbonaceous [5 day, 20 C]monthly averagereport only (lb/d)all year

How strict are these limits?

Cited limits by parameter: Pennsylvania'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/PA0031771 · MCP: https://passage-data.com/mcp