Calais Wastewater Treatment Facility
Calais, ME · Washington County · Publicly Owned Treatment Works
- Average flow
- 0.34 MGD
- Design flow
- 1.5 MGD
- NPDES permit
- ME0100129
- Administratively continued
- Permit expires
- November 2021
- Population served
- 3,123
- CWNS 2022
Calais Wastewater Treatment Facility is a publicly owned wastewater treatment works in Calais, Washington County, Maine treating an average of 0.34 million gallons per day against a permitted design capacity of 1.5 MGD, serving about 3,123 residents. Treatment on site includes biogas balloons, biological treatment, other, dechlorination, disinfection, chlorine/ chloramine, primary clarification or sedimentation and other unit processes. It discharges under NPDES permit ME0100129 (administratively continued), which expires in November 2021, with 11 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biogas balloons
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Biological Treatment, Other
unit processDechlorination
unit processDisinfection, chlorine/ chloramine
unit processPrimary Clarification or Sedimentation
unit processScreening
unit processUnlock exact unit counts →
Compliance snapshot (last 3 years)
- Total violations
- 11
- 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 Calais Wastewater Treatment Facility.
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Perry · 17 mi away
0.0097 MGD
Perry · 19 mi away
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Eastport · 21 mi away
0.02 MGD
Eastport · 24 mi away
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Lubec · 27 mi away
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East Machias · 32 mi away
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Machias · 34 mi away
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Whitneyville · 35 mi away
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Calais Wastewater Treatment Facility: 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 19, 2025.