Portage Des Sioux WWTP
Portage Des Sioux, MO 63373 · Saint Charles County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- —
- NPDES permit
- MO0107328
- Administratively continued
- Permit expires
- September 2024
- Population served
- 305
- CWNS 2022
Portage Des Sioux WWTP is a publicly owned wastewater treatment works in Portage Des Sioux, Saint Charles County, Missouri, serving about 305 residents. It discharges under NPDES permit MO0107328 (administratively continued), which expires in September 2024, with 18 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in November 2015.
Treatment technology
5 treatment structures and unit processes identified at Portage Des Sioux WWTP.
Available with a free Klarifi account
See the full treatment train at Portage Des Sioux WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 18
- Effluent violations
- 0
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 Portage Des Sioux WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Compliance actions
- $702,160
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Nov 2015
PORTAGE DES SIOUX
Administrative order · CWA, NPDES Permit Violations · Final Order No Penalty · Compliance actions $702,160
Source: EPA ECHO, civil enforcement case 07-2010-0153.
Full case history with a free Klarifi account
Every action against Portage Des Sioux WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
Decision-makers at Portage Des Sioux WWTP.
No verified contacts on file yet
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Nearby wastewater treatment plants in Missouri
Florissant · 9 mi away
22.75 MGD
St. Charles · 10 mi away
—
St. Charles · 11 mi away
4.2 MGD
Saint Peters · 17 mi away
5.65 MGD
Saint Charles · 18 mi away
4.45 MGD
St. Louis · 19 mi away
123.06 MGD
O'Fallon · 20 mi away
7.55 MGD
Old Monroe · 21 mi away
0.0025 MGD
Portage Des Sioux WWTP: 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 May 3, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Lift station · Sludge dewatering · all terms