AYER W W T P
NPDES ID: MAG590031
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 6 effluent violations.
Violations
June 30, 2026
Copper, total recoverable
39% over limit
Discharged 0.0057 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
115% over limit
Discharged 0.43 mg/L against a permitted limit of 0.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
114% over limit
Discharged 0.012 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
Copper, total recoverable
45% over limit
Discharged 0.00594 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
25% over limit
Discharged 0.007 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
25% over limit
Discharged 0.25 mg/L against a permitted limit of 0.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
E. coli
1286% over limit
Discharged 5667 MPN/100mL against a permitted limit of 409 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
67% over limit
Discharged 0.00684 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
114% over limit
Discharged 0.012 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
E. coli
240% over limit
Discharged 429 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEO)
DMR, Limited - Numeric Violation
February 28, 2026
E. coli
856% over limit
Discharged 1204 MPN/100mL against a permitted limit of 126 MPN/100mL (MO GEO)
DMR, Limited - Numeric Violation
Copper, total recoverable
82% over limit
Discharged 0.00746 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
79% over limit
Discharged 0.01 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
E. coli
1856% over limit
Discharged 8000 MPN/100mL against a permitted limit of 409 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
January 31, 2026
Copper, total recoverable
61% over limit
Discharged 0.009 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
61% over limit
Discharged 0.0066 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Copper, total recoverable
102% over limit
Discharged 0.0083 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
75% over limit
Discharged 0.0098 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2025
Copper, total recoverable
38% over limit
Discharged 0.00567 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
13% over limit
Discharged 0.0063 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2025
Copper, total recoverable
12% over limit
Discharged 0.00625 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2025
NOEC Static Renewal 7Day Chronic Ceriodaphnia dubia
0% over limit
Discharged 8.3 % against a permitted limit of 8.3 % (MO AV MN)
DMR, Limited - Overdue
Nickel, total [as Ni]
0% over limit
Discharged 0.004 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Copper, total recoverable
9% over limit
Discharged 0.00446 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
132% over limit
Discharged 0.013 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total [as Zn]
0% over limit
Discharged 0.026 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Copper, total [as Cu]
0% over limit
Discharged 9 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Carbon, tot organic [TOC]
0% over limit
Discharged 6.78 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Hardness, total [as CaCO3]
0% over limit
Discharged 218 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.68 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Aluminum, total [as Al]
0% over limit
Discharged 0.045 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
August 31, 2025
Copper, total recoverable
15% over limit
Discharged 0.00645 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
30% over limit
Discharged 0.005313 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Copper, total recoverable
14% over limit
Discharged 0.00468 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
18% over limit
Discharged 0.0066 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2025
Copper, total recoverable
41% over limit
Discharged 0.0079 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
7% over limit
Discharged 0.0044 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Copper, total recoverable
27% over limit
Discharged 0.0071 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
11% over limit
Discharged 0.00454 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Copper, total recoverable
17% over limit
Discharged 0.0048 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Copper, total recoverable
150% over limit
Discharged 0.014 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
29% over limit
Discharged 0.0053 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Copper, total recoverable
102% over limit
Discharged 0.008275 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
113% over limit
Discharged 0.0119 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2024
Copper, total recoverable
9% over limit
Discharged 0.00445 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
36% over limit
Discharged 0.0076 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2024
Copper, total recoverable
5% over limit
Discharged 0.0059 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
7% over limit
Discharged 0.0044 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Copper, total recoverable
33% over limit
Discharged 0.00546 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
NOEC Static Renewal 7Day Chronic Ceriodaphnia dubia
25% over limit
Discharged 6.25 % against a permitted limit of 8.3 % (MO AV MN)
DMR, Limited - Numeric Violation
Copper, total recoverable
46% over limit
Discharged 0.0082 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
August 31, 2024
Aluminum, total recoverable
7% over limit
Discharged 0.099 mg/L against a permitted limit of 0.0925 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
9% over limit
Discharged 0.00446 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
11% over limit
Discharged 0.0062 mg/L against a permitted limit of 0.0056 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
85% over limit
Discharged 0.37 mg/L against a permitted limit of 0.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Phosphorus, total [as P]
45% over limit
Discharged 0.29 mg/L against a permitted limit of 0.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
11% over limit
Discharged 0.00456 mg/L against a permitted limit of 0.0041 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Aluminum, total recoverable
41% over limit
Discharged 0.13000001 mg/L against a permitted limit of 0.0925 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)