Preparation

• Most building code regulations require most new construction and remodeling projects, as well as existing kitchens, to install grease traps in order to treat any grease and fats. In the majority of states, the device must be installed by a state-certified plumber and serviced and maintained by an approved contractor. Generally, you can install up to four fixtures on a grease trap. Install a flow device or restricting mechanism that has been approved by your municipality. The device must have the capacity to limit the flow to the grease trap to the trap's capacity.
  
  

Installation

• It's best to check with your local code office to determine the proper size grease trap for your needs before you go out and buy one. A grease trap receives water from a variety of sources, including dishwashers, floor drains, pot sinks and mat washing areas. Connect the fixture drain to the flow pipe. Usually a p-trap leading from the fixture is not required. However, you may have to put in a debris strainer basket on the section of pipe leading to the regulatory valve. Check with your local plumbing codes. Install a clean-out tee in the line before you connect the restricting device. This will allow you access the line to clean out waste.
  
  Place the grease trap as close as you can to the fixtures it will be servicing. You'll appreciate the easy access to the trap when it's time to clean, service or remove it. Attach the flow control valve to the flow line, which is the horizontal pipe underneath the fixture. Install a vent, or air intake. Make sure that the vent connection is at the top of the flow control fitting. The connection needs to be piped up and positioned higher than the source or drain.
  
  Follow the manufacturer's instruction for attaching the flow pipe to the grease trap inlet. Generally, the inlets and outlets of most grease traps have "no-hub fittings." This basically means they have plain ends, which allows you to make easy connections to a variety of materials, such as plastic, copper or pipe. Install another clean-out tee before you connect to the building or municipal drainage and sewer systems.