Sterling WWTP
Sterling, IL · Whiteside County · Publicly Owned Treatment Works
- Average flow
- 4.31 MGD
- Design flow
- 9 MGD
- NPDES permit
- IL0060569
- Administratively continued
- Permit expires
- September 2024
- Population served
- 14,764
- CWNS 2022
Sterling WWTP is a publicly owned wastewater treatment works in Sterling, Whiteside County, Illinois treating an average of 4.31 million gallons per day against a permitted design capacity of 9 MGD, serving about 14,764 residents. Treatment on site includes aerated lagoons. It discharges under NPDES permit IL0060569 (administratively continued), which expires in September 2024, with 5 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Aerated lagoons
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Compliance snapshot (last 3 years)
- Total violations
- 5
- Effluent violations
- 5
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Sterling WWTP.
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Nearby wastewater treatment plants in Illinois
Milledgeville · 11 mi away
0.09 MGD
Tampico · 13 mi away
0.05 MGD
Prophetstown · 14 mi away
0.15 MGD
Polo · 14 mi away
0.23 MGD
Chadwick · 16 mi away
0.04 MGD
Walnut · 19 mi away
0.08 MGD
Lanark · 21 mi away
0.31 MGD
Erie · 21 mi away
0.03 MGD
Sterling WWTP: 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 September 1, 2025.