City Of Sioux City STP
Sioux City, IA · Woodbury County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 28.73 MGD
- NPDES permit
- IA0043095
- Effective
- Permit expires
- January 2031
- Population served
- 94,220
- CWNS 2022
City Of Sioux City STP is a publicly owned wastewater treatment works in Sioux City, Woodbury County, Iowa, serving about 94,220 residents. Treatment on site includes clarifiers, biogas silos. It discharges under NPDES permit IA0043095 (effective), which expires in January 2031, with 10 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
- 10
- Effluent violations
- 10
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Capital improvement projects in Sioux City
Sioux City's capital improvement plan lists 28 water, sewer and wastewater line items worth $260M starting 2026–2028. The largest budgeted items are shown here.
All water and sewer capital projects in Sioux City →
| Project | Budget | Years |
|---|---|---|
| WWTP Facility Plan Improvements | $170,000,000 | 2027–2028 |
| Annual Water System Improvements | $12,051,000 | 2026–2030 |
| Outer Drive Pressure and Storage | $11,738,200 | 2028–2028 |
| Annual Sanitary Sewer Improvements | $11,460,000 | 2026–2030 |
| Annual Undersized Water Main Replacements | $9,390,000 | 2026–2030 |
Full project details — scope, funding source, engineering consultant and the decision-makers behind each project — are available in Klarifi, along with similar wastewater capital projects in other cities.
Key contacts
2 verified contacts for City Of Sioux City STP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at City Of Sioux City STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Iowa
Lawton · 10 mi away
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Salix · 11 mi away
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Hinton · 12 mi away
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Moville · 15 mi away
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Merrill · 20 mi away
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Hornick · 21 mi away
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Kingsley · 22 mi away
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Westfield · 24 mi away
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City Of Sioux City 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.