Grease and cooking oil are “hydrophobic,” which means they prefer to cling to surfaces that are free of water.

Grease will build from the top down in the sewer line. As the wastewater flows through the sewer line the grease continues to build restricting the flow of wastewater.

Eventually, grease will form a blockage in the sewer line.

In addition to household and business sewer lines clogging, cooking oil and grease in the wastewater can cause sewer lift station failures, wastewater treatment plant problems, and subsequently environmental concerns.

Grease has the potential to cause the City to violate its discharge requirements and affect the water quality of San Joaquin River.

Grease is one waste that the sewer system cannot handle and therefore needs to be kept out of the system.

How to Dispose of Grease and Cooking Oil

It is better to put grease in the garbage instead of the drain. Spent grease and cooking oil can be placed in a jar, coffee can, or other suitable container. After it has cooled, seal the container, wrap it in newspaper, then placed it in the household trash

Waste food products containing fats, cooking oil, or grease can be placed in a plastic bag or other suitable container then disposed along with the household trash instead of through the garbage disposal

Food service establishments require a grease interceptor to properly remove oil and grease.

Chemical Usage

Chemicals used to undo sewer clogs flow along the bottom of the drain pipe. If used frequently, the chemicals can deteriorate the bottom of the sewer pipe creating problems later for the homeowner or business.

Detergents, hot water, and chemicals do not remove grease. They merely allow grease to go into solution (emulsify it). When the emulsified solution contacts cooler water or piping, the grease re-coagulates causing problems downstream in the homeowner’s or business private sewer service line, the city sewer main, and at the Waste Water Treatment Plant (WWTP).

Help Reduce Costs

With your cooperation the City can reduce sewer backups, lower maintenance costs, and keep the sewer system operating smoothly.


Questions – Please call the Environmental Control Division at (209) 385-6204.