Helena, City of - Helena Municipal Water and Sewer System

NPDES permit AR0043389 · Major POTW · administratively continued, expires 2026-02-28 · EPA's file as of 2026-09-19

Check this month's numbers before you file

This permit expired on 2026-02-28 and is administratively continued: its last limits keep applying until a new permit is issued, and EPA still expects the reports.

EPA's record, 2025-09-01 to 2026-08-31

6values over a limit
12required values missing, on 1 form(s)
3of 13 forms filed late

Last period with anything received: 2026-07-31. Most often over: Oxygen, dissolved [DO] (4), Coliform, fecal general (2).

Reporting

Reports are due about 25 days after each monitoring period ends (read off this permit's own late-day counts in EPA's filings).

Limits in force (33)

OutfallParameterStatisticLimitMonths
001Oxygen, dissolved [DO]INST MIN >= 2 mg/L all year
001BOD, 5-day, 20 deg. CMO AVG <= 30 mg/L all year
001BOD, 5-day, 20 deg. C7 DA AVG <= 45 mg/L all year
001BOD, 5-day, 20 deg. CMO AVG <= 425.3 lb/d all year
001pHMINIMUM >= 6 SU all year
001pHMAXIMUM <= 10.5 SU all year
001Solids, total suspendedMO AVG <= 90 mg/L all year
001Solids, total suspended7 DA AVG <= 135 mg/L all year
001Solids, total suspendedMO AVG <= 1276 lb/d all year
001Nitrite + Nitrate total [as N]MO AVG report only all year
001Nitrite + Nitrate total [as N]7 DA AVG report only all year
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]7 DA AVG report only all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantDAILY MX report only all year
001Coliform, fecal general30DA GEO <= 200 #/100mL May, Jun, Jul, Aug, Sep
001Coliform, fecal general30DA GEO <= 1000 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
001Coliform, fecal general7 DA GEO <= 400 #/100mL May, Jun, Jul, Aug, Sep
001Coliform, fecal general7 DA GEO <= 2000 #/100mL Jan, Feb, Mar, Apr, Oct, Nov, Dec
001OverflowsMO TOTAL report only all year
001Overflow volume [SS0 volume, CSO volume]MO TOTAL report only all year
TX1Whole effluent toxicity - retest #148HR MIN report only all year
TX1Whole effluent toxicity - retest #248HR MIN report only all year
TX1WET, sublethal retest #148HR MIN report only all year
TX1WET, sublethal retest #248HR MIN report only all year
TX1Whole Effluent Toxicity - Retest #348HR MIN report only all year
TX1Whole Effluent Toxicity, Sub-Lethal Retest #348HR MIN report only all year
TX1Low Flow Pass/Fail Static Renewal 48Hr Acute Daphnia pulex48HR MIN report only all year
TX1LF Pass/Fail Static Renewal 48Hr Acute Pimephales promelas48HR MIN report only all year
TX1NOAEC Lethal Statis Renewal 48 Hr Acute Daphnia pulex48HR MIN report only all year
TX1NOAEC Lethal Static Renewal 48Hr acute Pimephales promelas48HR MIN report only all year
TX1Coef Of Var Static Renewal 48Hr Acute D. pulex48HR MIN report only all year
TX1Coef Of Var Static Renewal 48Hr Acute Pimephales promelas48HR MIN report only all year

Built from EPA's ECHO bulk files. EPA's file, not the permit document, is the source: read your permit. Check a report before you file it · All states