Grease Trap Pumping

We all know grease shouldn’t be dumped down the drain. But did you know that an estimated three billion pounds of fats, oil and grease (FOG) is dumped into wastewater by restaurants in the United States every year?  It is the number-one cause of sewer clogs and backups, costing taxpayers an estimated $25 billion per year*. 

Because grease is such a problem for sewers and septic systems, all restaurants, hotels, hospitals, schools, bars and supermarkets that prepare food are required by local ordinances to have a grease trap or grease interceptor. Grease traps are regulated not only by plumbing code on the installation side; the maintenance of grease traps is also regulated. 

 What’s the difference between a grease trap and a grease interceptor? They are essentially the same thing. An indoor device unit located under or near the sink where kitchen wastewater is disposed of is often referred to as a “grease trap.” A larger unit typically located under the ground outside the restaurant is commonly referred to as a “grease interceptor.” Both grease traps and interceptors work similar to a septic tank, separating solids with a series of baffles. FOG particles float to the top of the tank as they cool, while heavier solids sink to the bottom. Water is able to flow freely into the exit drain without carrying the FOG – provided the tank is pumped regularly. 

 How often should I pump my grease tank? How often to pump depends on the volume of wastewater produced and the size of the system. Most requirements are similar to septic tanks – that is, not to exceed 25% solids. For a grease trap under the sink, this could mean once a week or once a month. For a below-ground grease interceptor, restaurants may be required to pump monthly or every six months. Wastewater taken from the tank must be transported by an approved wastewater hauler and taken to an appropriate facility. 

*Wall Street Journal, June 4, 2001 https://www.wsj.com/articles/SB991600980767316234