Wastewater Treatment Facilities

For over 100 years, the City of Modesto has been treating wastewater to protect human health and the environment.

The City of Modesto owns and operates two wastewater treatment facilities: Sutter and Jennings. Modesto’s wastewater is treated to meet the stringent Federal and State regulatory requirements. An average of 20 million gallons of Modesto’s wastewater is treated per day at Sutter, and nearly 15 million of those gallons are further treated at Jennings to tertiary (recycled water) levels.

The wastewater is screened and clarified at the Sutter Primary Treatment Facility, which removes inorganic and settleable organic wastes. The inorganic solids are sent to the landfill, while organic solids are digested and converted to nutrient-rich biosolids. The wastewater is then pumped seven miles to Jennings Treatment Facility.

At Jennings, 14.9 million gallons are treated each day at the City’s Tertiary Treatment Plants. This water is then discharged into the Delta-Mendota Canal to be used for irrigation by the Del Puerto Water District.

The remaining wastewater is treated to secondary levels through fixed film reactors and facultative ponds and then stored for irrigation. This water is blended with seasonal cannery process water and applied alongside the nutrient-rich biosolids from Sutter to a 2,450-acre fodder ranch at Jennings.

Wastewater Services Division