HELENA MUNICIPAL WATER AND SEWER SYSTEM
NPDES ID: AR0043389
T — SNC: Compliance schedule reporting violation
The facility was more than 30 days late reporting progress on its compliance schedule.
This quarter: 2 effluent violations.
Violations
April 30, 2026
Coliform, fecal general
Limit violation
Discharged 2420 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
39% over limit
Discharged 1.22 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
March 31, 2026
Oxygen, dissolved [DO]
32% over limit
Discharged 1.37 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
February 28, 2026
Coliform, fecal general
Limit violation
Discharged 2420 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
42% over limit
Discharged 1.16 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
December 31, 2025
Oxygen, dissolved [DO]
49% over limit
Discharged 1.03 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
August 31, 2025
Oxygen, dissolved [DO]
4% over limit
Discharged 1.93 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
May 31, 2025
Oxygen, dissolved [DO]
33% over limit
Discharged 1.35 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
April 30, 2025
Oxygen, dissolved [DO]
30% over limit
Discharged 1.4 mg/L against a permitted limit of 2 mg/L (INST MIN)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)