AVON STP, VILLAGE OF
NPDES ID: IL0021334
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: 2 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
86% over limit
Discharged 2.785 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
12% over limit
Discharged 4.24 mg/L against a permitted limit of 3.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, ammonia total [as N]
71% over limit
Discharged 9.77 mg/L against a permitted limit of 5.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
283% over limit
Discharged 5.743 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
157% over limit
Discharged 9.77 mg/L against a permitted limit of 3.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, ammonia total [as N]
250% over limit
Discharged 14 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
212% over limit
Discharged 18.7 mg/L against a permitted limit of 6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
January 31, 2026
Nitrogen, ammonia total [as N]
172% over limit
Discharged 16.3 mg/L against a permitted limit of 6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
136% over limit
Discharged 9.443 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Nitrogen, ammonia total [as N]
31% over limit
Discharged 7.83 mg/L against a permitted limit of 6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
66% over limit
Discharged 6.625 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Nitrogen, ammonia total [as N]
508% over limit
Discharged 9.118 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
67% over limit
Discharged 9.53 mg/L against a permitted limit of 5.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
151% over limit
Discharged 9.53 mg/L against a permitted limit of 3.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
August 31, 2025
Nitrogen, ammonia total [as N]
171% over limit
Discharged 9.5 mg/L against a permitted limit of 3.5 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
281% over limit
Discharged 5.34 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
38% over limit
Discharged 9.5 mg/L against a permitted limit of 6.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
214% over limit
Discharged 4.4 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
49% over limit
Discharged 5.21 mg/L against a permitted limit of 3.5 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Nitrogen, ammonia total [as N]
442% over limit
Discharged 7.593 mg/L against a permitted limit of 1.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
182% over limit
Discharged 9.88 mg/L against a permitted limit of 3.5 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
43% over limit
Discharged 9.88 mg/L against a permitted limit of 6.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
May 31, 2025
Nitrogen, ammonia total [as N]
54% over limit
Discharged 8.76 mg/L against a permitted limit of 5.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
194% over limit
Discharged 4.415 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
131% over limit
Discharged 8.76 mg/L against a permitted limit of 3.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Nitrogen, ammonia total [as N]
61% over limit
Discharged 2.413 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Nitrogen, ammonia total [as N]
64% over limit
Discharged 9.34 mg/L against a permitted limit of 5.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
122% over limit
Discharged 100 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
51% over limit
Discharged 56 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
236% over limit
Discharged 5.035 mg/L against a permitted limit of 1.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
146% over limit
Discharged 9.34 mg/L against a permitted limit of 3.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
102% over limit
Discharged 12.1 mg/L against a permitted limit of 6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
132% over limit
Discharged 9.283 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
August 1, 2026 (4 days ago)