Marengo City Of STP
Off Of East South Street, East, Marengo, IA 52301 · Iowa County · Publicly Owned Treatment Works
- Average flow
- 0.31 MGD
- Design flow
- 1.77 MGD
- NPDES permit
- IA0047937
- Administratively continued
- Permit expires
- June 2026
- Population served
- 2,650
- CWNS 2022
Marengo City Of STP is a publicly owned wastewater treatment works in Marengo, Iowa County, Iowa treating an average of 0.31 million gallons per day against a permitted design capacity of 1.77 MGD, serving about 2,650 residents. It discharges under NPDES permit IA0047937 (administratively continued), which expires in June 2026, with 102 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in November 2016.
Treatment technology
2 treatment structures and unit processes identified at Marengo City Of STP.
Available with a free Klarifi account
See the full treatment train at Marengo City Of STP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 102
- Effluent violations
- 94
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 Marengo City Of STP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Compliance actions
- $2.5M
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Nov 2016
CITY OF MARENGO, IOWA
Administrative order · CWA, NPDES Permit Violations · Final Order No Penalty · Compliance actions $2.5M
Source: EPA ECHO, civil enforcement case 07-2011-0289.
Full case history with a free Klarifi account
Every action against Marengo City Of STP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
1 verified contact for Marengo City Of STP, with validated emails and direct phone numbers.
Unlock 1 verified contact
Names, validated emails and direct phone numbers for decision-makers at Marengo City Of STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Iowa
Marengo · 6 mi away
—
Watkins · 8 mi away
0.002 MGD
Blairstown · 8 mi away
0.08 MGD
Homestead · 9 mi away
0.05 MGD
Williamsburg · 9 mi away
0.44 MGD
Amana · 10 mi away
0.12 MGD
Norway · 10 mi away
0.08 MGD
Walford · 12 mi away
0.17 MGD
Marengo City Of STP: 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 January 23, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Sludge dewatering · Biological nutrient removal · all terms