Grease traps capture the oil and grease from the flow of wastewater by slowing down the flow of hot greasy water through the grease trap (actually a tank) and allowing it to cool. As it cools, the grease and oil separate out of the water and float to the top of the trap. The cooler water continues to flow down the drain pipe to the sewer while baffles prevent the accumulated grease and oil from flowing out of the grease trap. 

The size of the grease trap depends largely on how much waste your business produces and how often you perform trap maintenance. Grease traps may be located inside or outside of the building. Traps that are located inside the building tend to be smaller and require more frequent maintenance. Traps that are located outside the building tend to be larger and may be less disruptive to maintain. Outside grease traps will operate differently in winter versus summer and are more prone to clogging during cold weather. As a business owner/manager, you should know where the grease trap, drain lines, and clean-out are located at your restaurant.