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Uwchlan TWP Muni Auth Chester Cnty

Sewage treatment plant, Exton, Pennsylvania. NPDES permit PA0054917, in force until Feb 28, 2029. Last 12 months: over a limit 21 times (last June 2026), 27 required values missing. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form A monthly (27 values), form Q quarterly (5 values)
Last report on file
June 2026
Oct 2024 – Sep 2025
35 values over a limit, 0 required values missing, 0 of 16 reports late

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

All 21 values over a limit
Period endingParameterReportedLimitOver by
October 2025BOD, carbonaceous [5 day, 20 C], weekly average12 mg/L≤ 9 mg/L33%
October 2025Coliform, fecal general, instantaneous maximum3700 #/100mL≤ 1000 #/100mL270%
October 2025Nitrogen, ammonia total [as N], monthly average4.58 mg/L≤ .8 mg/L473%
October 2025Nitrogen, ammonia total [as N], monthly average7.6≤ 3.1 lb/d145%
November 2025Coliform, fecal general, geometric mean323 #/100mL≤ 200 #/100mL62%
November 2025Coliform, fecal general, instantaneous maximum11700 #/100mL≤ 1000 #/100mL1070%
November 2025Phosphorus, total [as P], monthly average1.99 mg/L≤ 1.6 mg/L24%
December 2025BOD, carbonaceous [5 day, 20 C], monthly average17 mg/L≤ 12 mg/L42%
December 2025BOD, carbonaceous [5 day, 20 C], weekly average35 mg/L≤ 18 mg/L94%
December 2025Coliform, fecal general, geometric mean354 #/100mL≤ 200 #/100mL77%
December 2025Coliform, fecal general, instantaneous maximum20000 #/100mL≤ 1000 #/100mL1900%
December 2025Nitrogen, ammonia total [as N], monthly average15.9≤ 9.3 lb/d71%
December 2025Nitrogen, ammonia total [as N], monthly average9.47 mg/L≤ 2.4 mg/L295%
December 2025Solids, total suspended, monthly average27 mg/L≤ 20 mg/L35%
December 2025Solids, total suspended, weekly average74 mg/L≤ 30 mg/L147%
January 2026Coliform, fecal general, instantaneous maximum20000 #/100mL≤ 1000 #/100mL1900%
January 2026Nitrogen, ammonia total [as N], monthly average< 3.14 mg/L≤ 2.4 mg/L31%
February 2026Coliform, fecal general, instantaneous maximum5900 #/100mL≤ 1000 #/100mL490%
February 2026Solids, total suspended, monthly average30 mg/L≤ 20 mg/L50%
February 2026Solids, total suspended, weekly average37 mg/L≤ 30 mg/L23%
June 2026Phosphorus, total [as P], monthly average1.51 mg/L≤ .8 mg/L89%

Limits in force (40)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]instantaneous minimum≥ 6 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≤ 20 mg/Lall year
Solids, total suspendedweekly average≤ 30 mg/Lall year
Solids, total suspendedmonthly average≤ 79.2 lb/dall year
Solids, total suspendedweekly average≤ 118.8 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 average≤ 50 mg/Lall year
Nitrogen, total [as N]monthly average≤ 198 lb/dall year
Nitrogen, ammonia total [as N]monthly average≤ .8 mg/LMay–Oct
Nitrogen, ammonia total [as N]monthly average≤ 2.4 mg/LJan, Feb, Mar, Apr, Nov, Dec
Nitrogen, ammonia total [as N]monthly average≤ 3.1 lb/dMay–Oct
Nitrogen, ammonia total [as N]monthly average≤ 9.3 lb/dJan, Feb, Mar, Apr, Nov, Dec
Phosphorus, total [as P]monthly average≤ .8 mg/LApr–Oct
Phosphorus, total [as P]monthly average≤ 1.6 mg/LJan, Feb, Mar, Nov, Dec
Phosphorus, total [as P]monthly average≤ 3.1 lb/dApr–Oct
Phosphorus, total [as P]monthly average≤ 6.2 lb/dJan, Feb, Mar, Nov, Dec
Copper, total [as Cu]quarterly averagereport only (mg/L)all year
Copper, total [as Cu]daily maximumreport only (mg/L)all year
Zinc, total [as Zn]quarterly averagereport only (mg/L)all year
Zinc, total [as Zn]daily maximumreport only (mg/L)all year
Ultraviolet light intensitydaily minimumreport only (uW/cm2)all year
Ultraviolet light intensitymonthly averagereport 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
E. coliinstantaneous maximumreport only (#/100mL)all year
Coliform, fecal generalgeometric mean≤ 200 #/100mLall year
Coliform, fecal generalinstantaneous maximum≤ 1000 #/100mLall year
BOD, carbonaceous [5 day, 20 C]monthly average≤ 6 mg/LMay–Oct
BOD, carbonaceous [5 day, 20 C]monthly average≤ 12 mg/LJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]weekly average≤ 9 mg/LMay–Oct
BOD, carbonaceous [5 day, 20 C]weekly average≤ 18 mg/LJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]monthly average≤ 23.4 lb/dMay–Oct
BOD, carbonaceous [5 day, 20 C]monthly average≤ 46.8 lb/dJan, Feb, Mar, Apr, Nov, Dec
BOD, carbonaceous [5 day, 20 C]weekly average≤ 35 lb/dMay–Oct
BOD, carbonaceous [5 day, 20 C]weekly average≤ 70 lb/dJan, Feb, Mar, Apr, Nov, Dec

New limits from Mar 1, 2028

ParameterNew limitNew or tighterMedian, last 12 months× new limit
Copper, total [as Cu], daily maximum0.17 lb/dnew——
Copper, total [as Cu], daily maximum0.043 mg/Lnew0.013 mg/L (3 values)0.302×
Copper, total [as Cu], quarterly average0.028 mg/Lnew0.013 mg/L (3 values)0.464×
Copper, total [as Cu], quarterly average0.11 lb/dnew——

How strict are these limits?

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

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Your permit document is the final word. As JSON: /api/v1/permits/PA0054917 · MCP: https://passage-data.com/mcp