Oskaloosa SW STP
Oskaloosa, IA · Mahaska County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 3 MGD
- NPDES permit
- IA0038521
- Administratively continued
- Permit expires
- March 2026
- Population served
- 6,373
- CWNS 2022
Oskaloosa SW STP is a publicly owned wastewater treatment works in Oskaloosa, Mahaska County, Iowa, serving about 6,373 residents. Treatment on site includes clarifiers, uncovered lagoons, biogas silos, biogas balloons. It discharges under NPDES permit IA0038521 (administratively continued), which expires in March 2026, with 5 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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Uncovered lagoons
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Biogas silos
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Biogas balloons
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Compliance snapshot (last 3 years)
- Total violations
- 5
- Effluent violations
- 5
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
2 verified contacts for Oskaloosa SW STP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Oskaloosa SW STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Iowa
Beacon · 1 mi away
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University Park · 3 mi away
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Oskaloosa · 4 mi away
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Oskaloosa · 7 mi away
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Leighton · 9 mi away
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Eddyville · 9 mi away
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Rose Hill · 10 mi away
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Fremont · 12 mi away
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Oskaloosa SW 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 March 16, 2025.