Colona - Green Rock Regional STP
Colona, IL · Henry County · Publicly Owned Treatment Works
- Average flow
- 0.26 MGD
- Design flow
- —
- NPDES permit
- ILL059757
- Effective
- Permit expires
- December 2030
- Population served
- 8,161
- CWNS 2022
Colona - Green Rock Regional STP is a publicly owned wastewater treatment works in Colona, Henry County, Illinois treating an average of 0.26 million gallons per day, serving about 8,161 residents. It discharges under NPDES permit ILL059757 (effective), which expires in December 2030, with 17 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
- 17
- Effluent violations
- 15
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for Colona - Green Rock Regional STP, with validated emails and direct phone numbers.
Unlock 1 verified contact
Names, validated emails and direct phone numbers for decision-makers at Colona - Green Rock Regional STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Illinois
East Moline · 6 mi away
3.74 MGD
Moline · 8 mi away
2.72 MGD
Orion · 8 mi away
0.3 MGD
Geneseo · 9 mi away
0.36 MGD
Moline · 10 mi away
3.43 MGD
Milan · 12 mi away
0.03 MGD
Milan · 12 mi away
0.52 MGD
Cambridge · 13 mi away
0.37 MGD
Colona - Green Rock Regional 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 18, 2025.