DUNCANNON STP
NPDES ID: PA0021245
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
Violations
February 28, 2026
Phosphorus, total [as P]
33% over limit
Discharged 2.66 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Phosphorus, total [as P]
65% over limit
Discharged 3.3 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
E. coli
0% over limit
Discharged 1 MPN/100mL against a permitted limit of 0 MPN/100mL (DAILY MX)
DMR, Monitor Only - Overdue
November 30, 2025
Solids, total suspended
0% over limit
Discharged 816.74599314 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 428 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 4.99399996 kg/d against a permitted limit of 83.98999929 kg/d (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 8.4 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Overdue
Coliform, fecal general
0% over limit
Discharged 4 MPN/100mL against a permitted limit of 2000 MPN/100mL (GEO MEAN)
DMR, Limited - Overdue
Phosphorus, Total
0% over limit
Discharged 118.947999 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Nitrogen, Kjeldahl Total
0% over limit
Discharged 45.85399961 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 2.72399998 kg/d against a permitted limit of 111.22999907 kg/d (WKLY AVG)
DMR, Limited - Overdue
Nitrogen, Kjeldahl, total [as N]
0% over limit
Discharged 1.87 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, Total
0% over limit
Discharged 83.98999929 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Chlorine, total residual
0% over limit
Discharged 0.2 mg/L against a permitted limit of 0.5 mg/L (MO AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 3 mg/L against a permitted limit of 40 mg/L (WKLY AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 2.72399998 kg/d against a permitted limit of 68.09999943 kg/d (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 6 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 362.29199696 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 7.86 SU against a permitted limit of 6 SU (DAILY MN)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 5.90199995 kg/d against a permitted limit of 124.84999895 kg/d (WKLY AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 492 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, total [as N]
0% over limit
Discharged 3.42 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, Ammonia Total
0% over limit
Discharged 2.26999998 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Coliform, fecal general
0% over limit
Discharged 196 MPN/100mL against a permitted limit of 10000 MPN/100mL (INST MAX)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.272 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Phosphorus, total [as P]
138% over limit
Discharged 4.76 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Overdue
Phosphorus, total [as P]
138% over limit
Discharged 4.76 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 3 mg/L against a permitted limit of 25 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.1 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 554.33399534 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
Nitrite + Nitrate total [as N]
0% over limit
Discharged 1.55 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.215 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Nitrite Plus Nitrate Total
0% over limit
Discharged 38.13599968 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 7 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 7.36 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Overdue
Phosphorus, total [as P]
0% over limit
Discharged 4.08599997 kg/d against a permitted limit of 5.44799995 kg/d (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 419.94999647 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
Chlorine, total residual
0% over limit
Discharged 0.43 mg/L against a permitted limit of 1.6 mg/L (INST MAX)
DMR, Limited - Overdue
October 31, 2025
Chlorine, total residual
0% over limit
Discharged 0.36 mg/L against a permitted limit of 1.6 mg/L (INST MAX)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 1.81599998 kg/d against a permitted limit of 68.09999943 kg/d (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 8 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Overdue
Phosphorus, total [as P]
0% over limit
Discharged 3.63199997 kg/d against a permitted limit of 5.44799995 kg/d (MO AVG)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 411 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Phosphorus, Total
0% over limit
Discharged 118.493999 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 2.26999998 kg/d against a permitted limit of 111.22999907 kg/d (WKLY AVG)
DMR, Limited - Overdue
Coliform, fecal general
0% over limit
Discharged 323 MPN/100mL against a permitted limit of 10000 MPN/100mL (INST MAX)
DMR, Limited - Overdue
pH
0% over limit
Discharged 7.99 SU against a permitted limit of 6 SU (DAILY MN)
DMR, Limited - Overdue
Nitrogen, Total
0% over limit
Discharged 77.63399935 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 428.1219964 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 8.29 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 301.45599747 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, Ammonia Total
0% over limit
Discharged 3.17799997 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Chlorine, total residual
0% over limit
Discharged 0.2 mg/L against a permitted limit of 0.5 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, Kjeldahl, total [as N]
0% over limit
Discharged 1.44 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.199 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 360 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.298 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Nitrogen, Kjeldahl Total
0% over limit
Discharged 35.8659997 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
Nitrogen, total [as N]
0% over limit
Discharged 3.1 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 4.99399996 kg/d against a permitted limit of 83.98999929 kg/d (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 6 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 3 mg/L against a permitted limit of 40 mg/L (WKLY AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 2 mg/L against a permitted limit of 25 mg/L (MO AVG)
DMR, Limited - Overdue
Phosphorus, total [as P]
134% over limit
Discharged 4.67 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Overdue
Phosphorus, total [as P]
134% over limit
Discharged 4.67 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
0% over limit
Discharged 8.28 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 6.80999994 kg/d against a permitted limit of 124.84999895 kg/d (WKLY AVG)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 509.38799572 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
Nitrite + Nitrate total [as N]
0% over limit
Discharged 1.68 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Coliform, fecal general
0% over limit
Discharged 11 MPN/100mL against a permitted limit of 2000 MPN/100mL (GEO MEAN)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.13 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 343.67799711 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
Nitrite Plus Nitrate Total
0% over limit
Discharged 42.22199965 kg against a permitted limit of 0 kg (MO TOTAL)
DMR, Monitor Only - Overdue
September 30, 2025
Nitrogen, Total
0% over limit
Discharged 0 kg against a permitted limit of 0 kg (ANNL TOT)
DMR, Monitor Only - Overdue
Phosphorus, Total
0% over limit
Discharged 0 kg against a permitted limit of 0 kg (ANNL TOT)
DMR, Monitor Only - Overdue
Nitrogen, Ammonia Total
0% over limit
Discharged 0 kg against a permitted limit of 0 kg (ANNL TOT)
DMR, Monitor Only - Overdue
Phosphorus, Total
0% over limit
Discharged 0 kg against a permitted limit of 818.10799313 kg (ANNL TOT)
DMR, Limited - Overdue
Nitrogen, Total
0% over limit
Discharged 0 kg against a permitted limit of 6136.26394844 kg (ANNL TOT)
DMR, Limited - Overdue
Phosphorus, total [as P]
40% over limit
Discharged 2.8 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2025
Phosphorus, total [as P]
45% over limit
Discharged 2.9 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
60% over limit
Discharged 1600 MPN/100mL against a permitted limit of 1000 MPN/100mL (INST MAX)
DMR, Limited - Numeric Violation
July 31, 2025
Phosphorus, total [as P]
20% over limit
Discharged 2.4 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Phosphorus, total [as P]
40% over limit
Discharged 2.8 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Phosphorus, total [as P]
45% over limit
Discharged 2.9 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Phosphorus, total [as P]
120% over limit
Discharged 4.4 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2024
Phosphorus, total [as P]
60% over limit
Discharged 3.2 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Phosphorus, Total
24% over limit
Discharged 1017.41399145 kg against a permitted limit of 818.10799313 kg (ANNL TOT)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (5 days ago)