Decorah City Of STP
Decorah, IA · Winneshiek County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 4.83 MGD
- NPDES permit
- IA0035220
- Effective
- Permit expires
- October 2027
- Population served
- 8,427
- CWNS 2022
Decorah City Of STP is a publicly owned wastewater treatment works in Decorah, Winneshiek County, Iowa, serving about 8,427 residents. Treatment on site includes clarifiers, biogas silos. It discharges under NPDES permit IA0035220 (effective), which expires in October 2027, with 3 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Compliance snapshot (last 3 years)
- Total violations
- 3
- Effluent violations
- 3
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
2 verified contacts for Decorah City Of STP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at Decorah City Of STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Iowa
Calmar · 10 mi away
—
Ossian · 11 mi away
0.07 MGD
Ridgeway · 12 mi away
—
Spillville · 12 mi away
—
Castalia · 13 mi away
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Fort Atkinson · 13 mi away
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Waukon · 14 mi away
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Postville · 17 mi away
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Decorah 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 February 3, 2025.