How to Clean a Grease Trap

Grease traps are designed to do just what the name implies, which is to trap fatty oils, greases, and sludge, and to separate the oils from water. The substances pass through a catching system, which gives them time to cool off and solidify, and the water passes through the drain as normal. This system must be maintained regularly in order to work effectively in keeping your grease trap clean. When done correctly, learning how to clean a grease trap will save you ample amounts of money for your business.


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    Detach the lid from the grease trap gently with a pry bar. Be sure to go slowly through this process, as there are gaskets for the grease trap located just under the cover. If you damage these, you will have to spend money to replace them.
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    Inspect the grease trap's parts once the lid is removed. You will be removing and replacing parts during cleaning, and you need to know where the components are located and how to install them to put them back in properly. For better results, it may help to draw a diagram of the trap's interior so that you can refer to during the re-installation process.
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    Insert a wooden dowel or measuring stick into the grease trap. Gently guide it to the bottom of the trap, and swirl it lightly in the trap so that the grease and oils mark the dowel. This can provide you with a guide to how much debris is in the trap.
    • Remove the dowel, and use a tape measure to determine how many inches of waste are present. Record the results in a FOG (fatty oils and grease) pump out report, which is issued by the Environmental Protection Agency (EPA).
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    Use a small bucket to remove any standing water from the tank of your grease trap. If you prefer, you can store the water in a larger bucket or trash bin, and pour it back into the drain after collecting the waste.
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    Remove the waste from your grease trap with the small bucket. Scoop the bucket in to the trap, and bring out the solidified waste. Place the waste in a water-tight container, such as a heavy-duty plastic trash bag.
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    Scrape down the lid and the sides of the trap with your bucket. Remove any large pieces of fat or oils that are attached to the trap. To achieve an even cleaner trap, you can use a wet/dry vacuum to suck out any smaller bits of waste.
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    Clean the lids, trap sides, and parts with soap and room-temperature water. Use a steel pot scrubber to remove excess waste and odor. Flush the screens and parts with water to remove the soap and debris.
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    Re-install the grease traps parts by following your diagram. Replace the lid once all the parts are secured and working.
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    Copy your FOG report for your records. Mail the original to the address listed on the report.


  • For optimal results, you should perform a vigorous cleaning a minimum of every 90 days. This will have multiple benefits, including minimizing foul odors emanating from the trap, preventing it from overflowing into your business or the street, and guaranteeing its effectiveness.
  • An alternative technology, the Grease Recovery Device does not require grease trap pumping or cleaning. Recovered grease does not go landfill. It is recyclable for future biodiesel use with the waste vegetable oil from a restaurant's deep-fryer.
  • Wait until the day before trash pickup in your area to clean the traps. This will minimize the time the waste must sit in your garbage, thereby also minimizing the odor.
  • A mask is recommended due to the rancid odors of the grease trap.
  • Grease trap cleaning should be a regular part of your facility's maintenance routine. The EPA requires that these traps remain clutter-free and functional. Failure to comply is a criminal offense in most locations.
  • There are many different methods available for disposal of grease trap waste. Rather than to just throw the debris in the garbage, which goes to a dump, consider available alternatives, such as companies that recycle the waste into usable bio fuel, garbage companies that use special disposal techniques for fatty liquids, oils, or grease.
  • Never use grease trap additives including bacteria or enzymes. These products push the grease from the trap into the sanitary sewer. The grease eventually re hardens and causes severe grease blockages. Grease trap additives are illegal in most states and every province throughout Canada.
  • Fats, oils, and grease (FOG) are lighter than water therefore it floats. Food solids sink and go to the bottom of the tank. Once a grease trap is 25% full over 60% of the fats, oils, and grease go directly down the drain and into the sanitary sewer. The percentage increases the more full of FOG the trap becomes. Grease traps should be cleaned and pumped out every 30 days.

Things You'll Need

  • Grease trap
  • Pry bar
  • Wooden dowel or stick
  • Tape measure
  • FOG pump out report
  • Bucket
  • Wet/dry vacuum (optional)
  • Liquid soap
  • Steel pot scrubber
  • Water source

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Categories: Car Maintenance and Repair