St. Tammany Parish Government - Castine Regional Sewage Treatment Plant
Mandeville, LA · St. Tammany County · Publicly Owned Treatment Works
- Average flow
- 0.48 MGD
- Design flow
- 1 MGD
- NPDES permit
- LA0120154
- Effective
- Permit expires
- August 2028
- Population served
- —
- CWNS 2022
St. Tammany Parish Government - Castine Regional Sewage Treatment Plant is a publicly owned wastewater treatment works in Mandeville, St. Tammany County, Louisiana treating an average of 0.48 million gallons per day against a permitted design capacity of 1 MGD. It discharges under NPDES permit LA0120154 (effective), which expires in August 2028, with 18 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Treatment structure data not yet analyzed for this facility.
Compliance snapshot (last 3 years)
- Total violations
- 18
- Effluent violations
- 18
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at St. Tammany Parish Government - Castine Regional Sewage Treatment Plant.
No verified contacts on file yet
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Mandeville · 6 mi away
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Covington · 6 mi away
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Madisonville · 8 mi away
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Madisonville · 9 mi away
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St. Tammany Parish Government - Castine Regional Sewage Treatment Plant: 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 27, 2025.