Mahnomen WWTP
104 W Madison Ave, PO Box 250, Mahnomen, MN 56557 · Mahnomen County · Publicly Owned Treatment Works
- Average flow
- 2.32 MGD
- Design flow
- 1.04 MGD
- NPDES permit
- MN0024066
- Effective
- Permit expires
- September 2029
- Population served
- 1,428
- CWNS 2022
Mahnomen WWTP is a publicly owned wastewater treatment works in Mahnomen, Mahnomen County, Minnesota treating an average of 2.32 million gallons per day against a permitted design capacity of 1.04 MGD, serving about 1,428 residents. It discharges under NPDES permit MN0024066 (effective), which expires in September 2029, with 71 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in November 2018.
Treatment technology
Treatment structures and unit processes at Mahnomen WWTP.
Treatment structure data not yet analyzed for this facility.
Compliance snapshot (last 3 years)
- Total violations
- 71
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for Mahnomen WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Compliance actions
- $76,369
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Nov 2018
Mahnomen AOC
Administrative order · CWA, NPDES Permit Violations · Final Order No Penalty · Compliance actions $76,369
EPA's description of the case:
“AOC to address compliance issues”
Source: EPA ECHO, civil enforcement case 05-2018-0306.
Full case history with a free Klarifi account
Every action against Mahnomen WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
Decision-makers at Mahnomen WWTP.
No verified contacts on file yet
Klarifi verifies plant and municipal decision-makers continuously. Start a free trial to browse contacts at nearby plants and flag this one for verification.
Nearby wastewater treatment plants in Minnesota
Waubun · 8 mi away
—
Bejou · 11 mi away
0.02 MGD
Ogema · 13 mi away
0.07 MGD
Gary · 14 mi away
—
White Earth · 15 mi away
0.09 MGD
Twin Valley · 15 mi away
—
Naytahwaush · 15 mi away
0.11 MGD
Winger Township · 16 mi away
—
Mahnomen WWTP: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026; facility record last updated May 3, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Lift station · Sludge dewatering · all terms