Colusa WWTP
Colusa, CA · Colusa County · Publicly Owned Treatment Works
- Average flow
- 0.46 MGD
- Design flow
- 0.7 MGD
- NPDES permit
- CA0078999
- Effective
- Permit expires
- May 2027
- Population served
- 5,760
- CWNS 2022
Colusa WWTP is a publicly owned wastewater treatment works in Colusa, Colusa County, California treating an average of 0.46 million gallons per day against a permitted design capacity of 0.7 MGD, serving about 5,760 residents. Treatment on site includes clarifiers, aerated lagoons, uncovered lagoons. It discharges under NPDES permit CA0078999 (effective), which expires in May 2027, with 67 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
- 67
- Effluent violations
- 67
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
2 verified contacts for Colusa WWTP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at Colusa WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in California
Williams · 7 mi away
—
Live Oak · 20 mi away
0.74 MGD
Yuba City · 23 mi away
5.05 MGD
Willows · 23 mi away
—
Marysville · 25 mi away
2.41 MGD
Olivehurst · 27 mi away
1.99 MGD
Oroville · 32 mi away
3.4 MGD
Smartsville · 39 mi away
0.01 MGD
Colusa 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 August 19, 2026.