Ontario (t) STP
Ontario, NY · Wayne County · Publicly Owned Treatment Works
- Average flow
- 0.5 MGD
- Design flow
- 1 MGD
- NPDES permit
- NY0027171
- Administratively continued
- Permit expires
- February 2023
- Population served
- 10,092
- CWNS 2022
Ontario (t) STP is a publicly owned wastewater treatment works in Ontario, Wayne County, New York treating an average of 0.5 million gallons per day against a permitted design capacity of 1 MGD, serving about 10,092 residents. Treatment on site includes clarifiers. It discharges under NPDES permit NY0027171 (administratively continued), which expires in February 2023, with 11 recorded violations 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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Compliance snapshot (last 3 years)
- Total violations
- 11
- Effluent violations
- 10
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Ontario (t) STP.
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Nearby wastewater treatment plants in New York
Walworth · 10 mi away
0.43 MGD
Sodus · 11 mi away
0.22 MGD
Macedon · 14 mi away
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Palmyra · 15 mi away
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Palmyra, Town Of · 15 mi away
0.62 MGD
Rochester · 15 mi away
—
Newark · 18 mi away
1.33 MGD
Lyons · 21 mi away
0.23 MGD
Ontario (t) STP: 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 22, 2025.