Maintaining Your Grease Trap

Maintaining your restaurant's grease trap or grease interceptor is a must for proper operation, and is required by the City of Abilene fats, oils and grease (FOG) Ordinance.


Cleaning a grease trap involves vacuuming all the contents, scraping built-up grease on the walls, and sucking up the remainder while rinsing with a pressure washer. This cleaning process should be done on large grease traps every 90 days or more frequently if needed. 

Small grease traps should be cleaned every 30 days or when the grease layer reaches 2 inches thick. Trip tickets - which verify who generated the grease, when the trap was cleaned, who cleaned it, how much was pumped out, when and where the grease was disposed of from each cleanout - must be maintained on-site for five years.

Pump Out Frequency

The pump-out frequency is how often the grease trap needs to be cleaned so that it functions effectively. This will vary depending on the size of the grease trap, the number of meals served, grease content of food, etc.

When to Clean

According to the FOG Ordinance:

  • Large grease traps must be cleaned at least every 90 days by a licensed transporter
  • Small grease traps must be cleaned at least every 30 days, also by a licensed transporter.
  • Some facilities may need to clean more often.

Your grease trap needs to be cleaned when the depth of the grease layer plus the depth of the solids layer is 25% of the depth of all three layers. The depth of the solids layer can be difficult to determine without a sampling tube, so it may be easier to check the depth of the grease layer with a rod or stick. 

Generally, when the grease layer is 5 to 6 inches thick in a large grease trap (2 inches for under-sink traps), the 25% rule has been met. If this amount of grease is accumulating long before the next scheduled pump out, then the trap needs to be cleaned more often.

Extensions to the Pumping Frequency

If your food facility hasn't met the 25% rule for two cycles at the minimum frequency, then you can request an extension to the pumping frequency. Requests will be reviewed and granted on a case by case basis. You will be required to provide documentation that the 25% rule has not been met for each of the two cleaning cycles. 

This is generally done by photographing the depth of the grease layer with a ruler or other appropriate scale in the photograph. Download the Request for Extension to Cleaning Frequency Form (PDF) and be sure to include your documentation so that it may be handled without delay.

Alternate Cleaning Schedules for Seasonal Facilities

For seasonal facilities or irregular usage such as concession stands, event venues, church kitchens, etc, an alternate schedule may be developed that will be appropriate for that facility. To request an alternate schedule, complete and return the Alternate Cleaning Schedule Request Form (PDF), which will be handled on a case by case basis.

Other Maintenance Tips

  • Recycle used fry oil. Considered a valuable commodity, some renderers may even pay you for it.
  • Wipe the grease off of pans with a dry paper towel before running them underwater. And, the prewashing station and dishwasher must drain into a grease trap.
  • Scrape excess food off of pots, pans, and plates and throw it away. Don't use the garbage disposal in the sink. When food scraps decompose in the grease trap, they release acids that eat through the walls of the grease trap, drastically reducing its lifespan.