MECHANICSBURG WWTP
NPDES ID: OH0022209
S — SNC: Compliance schedule violation
The facility missed a deadline in its compliance schedule by more than 90 days.
This quarter: 4 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
171% over limit
Discharged 6.1 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
14% over limit
Discharged 1.6 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
40% over limit
Discharged 2.8 kg/d against a permitted limit of 2 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
April 30, 2026
Phosphorus, total [as P]
44% over limit
Discharged 1.44 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Solids, total suspended
212% over limit
Discharged 49 kg/d against a permitted limit of 15.7 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
320% over limit
Discharged 11 kg/d against a permitted limit of 2.62 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
7% over limit
Discharged 16 mg/L against a permitted limit of 15 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
117% over limit
Discharged 6.5 mg/L against a permitted limit of 3 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
89% over limit
Discharged 3.3 kg/d against a permitted limit of 1.75 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
25% over limit
Discharged 2.5 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
56% over limit
Discharged 28 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Solids, total suspended
43% over limit
Discharged 15 kg/d against a permitted limit of 10.5 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
114% over limit
Discharged 28 kg/d against a permitted limit of 13.1 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
January 31, 2026
Nitrogen, ammonia total [as N]
114% over limit
Discharged 4.28 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
175% over limit
Discharged 8.25 mg/L against a permitted limit of 3 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
18% over limit
Discharged 3.08 kg/d against a permitted limit of 2.62 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
December 31, 2025
Phosphorus, total [as P]
21% over limit
Discharged 1.21 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Phosphorus, total [as P]
11% over limit
Discharged 1.66 mg/L against a permitted limit of 1.5 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Solids, total suspended
33% over limit
Discharged 16 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
66% over limit
Discharged 1.66 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
94% over limit
Discharged 35 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
October 31, 2025
E. coli, MTEC-MF
160% over limit
Discharged 328 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEOMN)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
12% over limit
Discharged 1.12 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
8% over limit
Discharged 13 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
238% over limit
Discharged 959 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
September 30, 2025
E. coli, MTEC-MF
2662% over limit
Discharged 3480 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEOMN)
DMR, Limited - Numeric Violation
Solids, total suspended
122% over limit
Discharged 40 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
226% over limit
Discharged 3.26 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
21% over limit
Discharged 1.7 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
117% over limit
Discharged 3.26 mg/L against a permitted limit of 1.5 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Solids, total suspended
42% over limit
Discharged 17 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
20% over limit
Discharged 2.7 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
8421% over limit
Discharged 24200 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
August 31, 2025
E. coli, MTEC-MF
3351% over limit
Discharged 9800 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
441% over limit
Discharged 682 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEOMN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
251% over limit
Discharged 7.9 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
200% over limit
Discharged 4.2 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
20% over limit
Discharged 2.7 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
20% over limit
Discharged 18 mg/L against a permitted limit of 15 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Solids, total suspended
15% over limit
Discharged 18 kg/d against a permitted limit of 15.7 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
34% over limit
Discharged 1.34 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
14% over limit
Discharged 1.6 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
217% over limit
Discharged 57 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
238% over limit
Discharged 960 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
Solids, total suspended
83% over limit
Discharged 22 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Nitrogen, ammonia total [as N]
51% over limit
Discharged 3.4 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
8421% over limit
Discharged 24200 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
Solids, total suspended
17% over limit
Discharged 21 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
298% over limit
Discharged 502 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEOMN)
DMR, Limited - Numeric Violation
May 31, 2025
E. coli, MTEC-MF
3351% over limit
Discharged 9800 MPN/100mL against a permitted limit of 284 MPN/100mL (WK GEOMN)
DMR, Limited - Numeric Violation
April 30, 2025
Solids, total suspended
148% over limit
Discharged 39 kg/d against a permitted limit of 15.7 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
320% over limit
Discharged 11 kg/d against a permitted limit of 2.62 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 2.7 kg/d against a permitted limit of 1.75 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
27% over limit
Discharged 3.8 mg/L against a permitted limit of 3 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
January 31, 2025
BOD, carbonaceous [5 day, 20 C]
33% over limit
Discharged 20 mg/L against a permitted limit of 15 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
110% over limit
Discharged 6.3 mg/L against a permitted limit of 3 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
6% over limit
Discharged 2.11 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Phosphorus, total [as P]
27% over limit
Discharged 1.27 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
6% over limit
Discharged 19 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
October 31, 2024
BOD, carbonaceous [5 day, 20 C]
147% over limit
Discharged 37 mg/L against a permitted limit of 15 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
278% over limit
Discharged 8.5 mg/L against a permitted limit of 2.25 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
150% over limit
Discharged 5 kg/d against a permitted limit of 2 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
17% over limit
Discharged 1.75 mg/L against a permitted limit of 1.5 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
75% over limit
Discharged 1.75 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
17% over limit
Discharged 1.4 kg/d against a permitted limit of 1.2 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
37% over limit
Discharged 18 kg/d against a permitted limit of 13.1 kg/d (WKLY MAX)
DMR, Limited - Numeric Violation
Solids, total suspended
56% over limit
Discharged 28 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
79% over limit
Discharged 2.5 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
50% over limit
Discharged 15 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
17% over limit
Discharged 14 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Phosphorus, total [as P]
66% over limit
Discharged 1.66 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
6% over limit
Discharged 19 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
11% over limit
Discharged 1.66 mg/L against a permitted limit of 1.5 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
August 31, 2024
Solids, total suspended
17% over limit
Discharged 21 mg/L against a permitted limit of 18 mg/L (WKLY MAX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
7% over limit
Discharged 1.07 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (5 days ago)