Mascoutah, City Of
Mascoutah, IL · Saint Clair County · Publicly Owned Treatment Works
- Average flow
- 0.55 MGD
- Design flow
- 5.25 MGD
- NPDES permit
- IL0025291
- Effective
- Permit expires
- April 2031
- Population served
- 7,468
- CWNS 2022
Mascoutah, City Of is a publicly owned wastewater treatment plant in Mascoutah, Saint Clair County, Illinois treating an average of 0.55 million gallons per day against a permitted design capacity of 5.25 MGD, serving about 7,468 residents. Treatment on site includes uncovered lagoons. It discharges under NPDES permit IL0025291 (effective), which expires in April 2031, with 0 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Uncovered lagoons
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Compliance snapshot (last 3 years)
- Total violations
- 0
- Effluent violations
- 0
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Mascoutah, City Of.
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Mascoutah, City Of: 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 August 3, 2026.