MASON WWTP
NPDES ID: MI0020435
D — SNC: Discharge monitoring report not received
The facility didn't submit its required discharge monitoring report.
Violations
January 31, 2026
Oxygen, dissolved [DO]
67% over limit
Discharged 2 mg/L against a permitted limit of 6 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
14% over limit
Discharged 12.5 mg/L against a permitted limit of 11 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2025
Oxygen, dissolved [DO]
48% over limit
Discharged 3.1 mg/L against a permitted limit of 6 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
October 29, 2025
Phosphorus, sludge, total, dry weight [as P]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Copper, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Potassium, sludge, total, dry weight [as K]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Nitrogen, sludge, total, dry weight [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Potassium, sludge, total, dry weight [as K]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 mg/L against a permitted limit of 840 mg/L (MO MAX)
DMR, Limited - Overdue
Phosphorus, sludge, total, dry weight [as P]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Nitrogen, total Kjeldahl
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Selenium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Selenium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Solids, total
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, sludge, total, dry weight [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Copper, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Copper, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 4300 mg/L (MO MAX)
DMR, Limited - Overdue
Solids, total
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Solids, total
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Nitrogen, total Kjeldahl
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 mg/L against a permitted limit of 57 mg/L (MO MAX)
DMR, Limited - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Nitrogen, sludge, total, dry weight [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 mg/L against a permitted limit of 7500 mg/L (MO MAX)
DMR, Limited - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MIN)
DMR, Monitor Only - Overdue
Nitrogen, total Kjeldahl
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 420 mg/L (MO MAX)
DMR, Limited - Overdue
Potassium, sludge, total, dry weight [as K]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Phosphorus, sludge, total, dry weight [as P]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Selenium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 100 mg/L (MO MAX)
DMR, Limited - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 85 mg/L (MO MAX)
DMR, Limited - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 mg/L against a permitted limit of 75 mg/L (MO MAX)
DMR, Limited - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 75 mg/L (MO MAX)
DMR, Limited - Overdue
June 30, 2025
BOD, carbonaceous [5 day, 20 C]
5% over limit
Discharged 4.2 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Toxicity, choice of species
96% over limit
Discharged 2.35 toxic against a permitted limit of 1.2 toxic (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
60% over limit
Discharged 32 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2025
BOD, carbonaceous [5 day, 20 C]
10% over limit
Discharged 4.4 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
30% over limit
Discharged 29.46459975 kg/d against a permitted limit of 22.69999981 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
265% over limit
Discharged 215.24139819 kg/d against a permitted limit of 59.0199995 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
35% over limit
Discharged 152.72559872 kg/d against a permitted limit of 113.49999905 kg/d (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Solids, total suspended
188% over limit
Discharged 496.08579583 kg/d against a permitted limit of 172.51999855 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
17% over limit
Discharged 468 MPN/100mL against a permitted limit of 400 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Coliform, fecal general
200% over limit
Discharged 600 MPN/100mL against a permitted limit of 200 MPN/100mL (MO GEOMN)
DMR, Limited - Numeric Violation
Solids, total suspended
19% over limit
Discharged 53.64 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
363% over limit
Discharged 1176.85879011 kg/d against a permitted limit of 254.23999786 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
20% over limit
Discharged 272.39999771 kg/d against a permitted limit of 226.99999809 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, suspended percent removal
7% over limit
Discharged 84 % against a permitted limit of 85 % (MINIMUM)
DMR, Limited - Numeric Violation
October 31, 2024
BOD, carbonaceous [5 day, 20 C]
8% over limit
Discharged 4.3 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
BOD, carbonaceous [5 day, 20 C]
15% over limit
Discharged 4.6 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Toxicity, choice of species
17% over limit
Discharged 1.4 toxic against a permitted limit of 1.2 toxic (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Solids, total suspended
58% over limit
Discharged 272.39999771 kg/d against a permitted limit of 172.51999855 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
52% over limit
Discharged 0.762 mg/L against a permitted limit of 0.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
8% over limit
Discharged 12.2579999 kg/d against a permitted limit of 11.3499999 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
430% over limit
Discharged 10.6 mg/L against a permitted limit of 2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
22% over limit
Discharged 4.7 mg/L against a permitted limit of 6 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
10% over limit
Discharged 24.96999979 kg/d against a permitted limit of 22.69999981 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
78% over limit
Discharged 4.85779996 kg/d against a permitted limit of 2.72399998 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
25% over limit
Discharged 5 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)