MSD Coldwater WWTP
Florissant, MO · St Louis County · Publicly Owned Treatment Works
- Average flow
- 14.3 MGD
- Design flow
- —
- NPDES permit
- MO0025160
- Effective
- Permit expires
- August 2031
- Population served
- 160,833
- CWNS 2022
MSD Coldwater WWTP is a publicly owned wastewater treatment works in Florissant, St Louis County, Missouri treating an average of 14.3 million gallons per day, serving about 160,833 residents. Treatment on site includes clarifiers, biogas silos, biological treatment, other, biosolids thickening, dechlorination and other unit processes. It discharges under NPDES permit MO0025160 (effective), which expires in August 2031, with 1 recorded violation 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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Biogas silos
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Biological Treatment, Other
unit processBiosolids Thickening
unit processDechlorination
unit processDisinfection, chlorine/ chloramine
unit processPrimary Clarification or Sedimentation
unit processScreening
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Compliance snapshot (last 3 years)
- Total violations
- 1
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
3 verified contacts for MSD Coldwater WWTP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at MSD Coldwater WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Missouri
Portage Des Sioux · 9 mi away
—
St. Louis · 10 mi away
90.1 MGD
St. Charles · 11 mi away
3.73 MGD
St. Charles · 14 mi away
—
Saint Charles · 16 mi away
4.04 MGD
Saint Peters · 18 mi away
4.83 MGD
St. Louis · 19 mi away
79.3 MGD
Valley Park · 21 mi away
10.4 MGD
MSD Coldwater 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 September 11, 2026; facility record last updated May 20, 2025.