FOG is Fats, Oils and Grease that are used to aid in the preparation of food, or that is produced during the preparation of food. FOG gets into the sewer system through sinks and drains as well as through poorly maintained grease traps and grease interceptors. FOG discharge affects the sewer system performance by clogging sewer pipes which causes Sanitary System Overflows (SSOs), thereby causing expensive property damage and health hazards.

For information on disposal of small amounts of FOG at your residence, please click here.  If you are a resident and you have a large amount of FOG, please read further and recycle your FOG through a licensed grease hauler or recycler only.  Do not dispose of large amounts of FOG at home.

The Districts FOG control program is required by and developed pursuant to the ‘Waste Discharge Requirements’ of Regional Water Quality Control Board, to prevent FOG related SSOs. This program is aimed to curb the amount of FOG that is discharged either directly or indirectly into the sanitary sewer by Food Service Establishments (FSEs). It is the responsibility of the FSEs to have their grease interceptors and traps adequately sized to effectively remove FOG used/produced at their facility. All such devices should be installed and maintained to ensure compliance with CVSan Code Section 4129 and 4130. As per CVSan code section 4130, though the minimum cleaning frequency required for all grease interceptors is 6 months, some establishments will find it necessary to clean their interceptors more often than what is required by the code.

According to CVSan code 4137, the District Inspector and other duly authorized employees of the District conducts inspection of FOG handling and practices at all FSEs within the jurisdiction.

Best Management Practices for Food Service Establishments:

The District recommends all FSEs to follow Best Management Practices (BMPs) that helps to prevent or reduce the introduction of FOG into the sanitary sewer system.
FOG control BMPs for food service establishments are as follows:

1.    Maintenance of Grease Interceptors and Traps:

Clean all grease abatement devices regularly to prevent grease discharged to the sewer.
       a.    The minimum cleaning frequency required for grease interceptors and traps are bi-annually and monthly, respectively. However, more frequent cleaning intervals may be necessary to ensure adequate grease removal.
       b.    All grease abatement devices should be maintained regularly such that the depth of floating FOG and settled solids accumulation do not exceed 25% of the hydraulic length, at any time. Thereby the working depth stays more than 75% for effective FOG separation.

2.    Disposal of Oily Food:

Minimize the amount of grease the facility sends to the grease trap or interceptor, by not pouring oil, grease, or large quantities of oily liquids such as sauces and salad dressings into sinks, grease interceptors or grease traps.  Scrape oily food remains into an organics bin/cart.

3.    Disposal of Cooking/Fryer Oil:

Do not pour yellow grease (used cooking/fryer oil) down the drain or in the trash. It is best to compost small amounts of cooking/fryer oil (in a paper milk or ice cream carton). Recycle large amounts of yellow grease through a licensed grease hauler or recycler. Store recyclable used oil in a separate sealed container. Provide secondary containment if placed outside the facility. Make sure that the containers are covered, spill-proof and have no leaks. Large amounts of used oil can also be transported by the food facilities in their own vehicles to the central collection point.

4.    Disposal of scraped grease:

It is best to compost small amounts of scraped grease (brown grease) from traps and cook-wares (in a paper milk or ice cream carton). The grease from traps and cook-wares should not go into the used oil recycle storage bin. Brown grease should not be mixed with yellow grease, unless the yellow grease hauler can recycle the entire contents when they are mixed. Large quantities of brown grease should go into regular garbage (solid waste) for pick up and disposal.

5.    Usage of Enzymes and Emulsifiers:

Do not use additives, including but not limited to biological or chemical agents, enzymes or surfactants acting as grease emulsifiers, into any grease interceptor or trap, for FOG remediation. Please note that chemicals used for odor control and drain cleaning is not prohibited from usage.

6.    Usage of Screens:

All drains should have screens, to keep solids out of the sink drains. These screens should be cleaned regularly to prevent kitchen drain blockage.

7.    Usage of Flow Control devices:

Flow control devices are installed at the inlet of indoor grease traps. As these devices aid gravity separation through their vents, they should be installed at the inlet at all times. Flow control devices should be cleaned regularly to prevent blockage due to accumulation of solid particles.

8.    Dry clean-up/Pre-wash:

Use rubber scrapers to remove food wastes from cookware, serving ware, utensils, and cooking surfaces prior to cleaning them with water. Paper towels can be used for mild scraping as an alternative to rubber scrapers. Do not use cloth towels for wiping or scraping. Make sure that the scraped grease or food is not dumped into the drain or grease trap. Use food grade paper to soak up oil grease under fryer baskets. After dry clean-up, begin washing with a hot pre-wash, then a scouring sink with detergent, then a rinse sink.

9.    Spill Handling:

Prevent spillage by,
       a.    Emptying containers before they are full
       b.    Using proper covers while transporting grease containers.

In case of spill, mop spill with absorbents such as cat litter or paper towel, before washing the spill with water. Train employees to control and clean up spills. Post notice to Employees providing emergency spill numbers.

10.   Documentation and Training:

Train staff on the best management practices of FOG handling and maintain documentation of grease abatement device maintenance for at least 3 years.

Frequently Asked Questions:

Q. What are Grease Abatement Devices (GADs)?

Q. Do I need a Grease Abatement Device?


Q. Can you recommend a maintenance schedule for Grease Abatement Devices?

Q. How do I know that my Grease Abatement Device is adequately sized?

Q. Who cleans the grease traps and interceptors?

Q. Who is a ‘Licensed Grease Hauler’?

Q. What should I do with yellow grease (used cooking/fryer oil)?


Q. How should FSEs stay compliant with the District Codes?

Some Useful References: