Onawa City Of STP
Onawa, IA · Monona County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 0.85 MGD
- NPDES permit
- IA0036145
- Administratively continued
- Permit expires
- April 2008
- Population served
- 2,906
- CWNS 2022
Onawa City Of STP is a publicly owned wastewater treatment works in Onawa, Monona County, Iowa, serving about 2,906 residents. Treatment on site includes clarifiers. It discharges under NPDES permit IA0036145 (administratively continued), which expires in April 2008, with 40 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Clarifiers
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Compliance snapshot (last 3 years)
- Total violations
- 40
- Effluent violations
- 40
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for Onawa City Of STP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Onawa City Of STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Iowa
Blencoe · 6 mi away
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Whiting · 8 mi away
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Moorhead · 14 mi away
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Little Sioux · 14 mi away
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Hornick · 15 mi away
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Pisgah · 15 mi away
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Soldier · 16 mi away
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Smithland · 17 mi away
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Onawa 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 September 11, 2026; facility record last updated May 17, 2025.