HILLSBORO STP, CITY OF
NPDES ID: IL0029203
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: 8 effluent violations, 4 permit schedule violations.
Violations
June 30, 2026
Solids, total suspended
21% over limit
Discharged 14.48 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
5% over limit
Discharged 420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
May 31, 2026
Solids, total suspended
56% over limit
Discharged 18.66 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
25% over limit
Discharged 30.1 mg/L against a permitted limit of 24 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
BOD, carbonaceous [5 day, 20 C]
10% over limit
Discharged 10.98 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
20% over limit
Discharged 3.61 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (5 months ago)
Last confirmed
September 15, 2026 (4 days ago)