Suffolk Co Sd#21 Suny
Stony Brook, NY · Suffolk County · Publicly Owned Treatment Works
- Average flow
- 2.09 MGD
- Design flow
- 2.5 MGD
- NPDES permit
- NY0206644
- Effective
- Permit expires
- November 2028
- Population served
- 27,152
- CWNS 2022
Suffolk Co Sd#21 Suny is a publicly owned wastewater treatment plant in Stony Brook, Suffolk County, New York treating an average of 2.09 million gallons per day against a permitted design capacity of 2.5 MGD, serving about 27,152 residents. Treatment on site includes clarifiers, carrousels / oxidation ditches. It discharges under NPDES permit NY0206644 (effective), which expires in November 2028, with 4 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Compliance snapshot (last 3 years)
- Total violations
- 4
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Suffolk Co Sd#21 Suny.
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Nearby wastewater treatment plants in New York
Kings Park · 6 mi away
0.24 MGD
Farmingville · 7 mi away
0.02 MGD
Patchogue · 12 mi away
0.38 MGD
Northport · 12 mi away
0.19 MGD
Shirley · 16 mi away
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Huntington · 16 mi away
1.58 MGD
Ocean Beach · 19 mi away
0.17 MGD
W Babylon · 21 mi away
26.7 MGD
Suffolk Co Sd#21 Suny: 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 March 12, 2025.