How to Install a Food Waste Disposal

Shut off the power to the electrical circuit that will power the disposal. Failure to do this can result in injury or death.

Install a ground fault circuit interrupter (GFCI) outlet under the sink. Run electrical wire from the circuit to a switch mounted above the sink, and then to the GFCI outlet.

Disconnect the waste line and remove the mounting assembly from the sink. Put a coil of plumber's putty around the disposal's flange and insert it into the sink drain hole.

Place a heavy object, such as a large book, on the flange to prevent it from shifting. Place the gasket according to the directions provided with your disposal unit, and slide the mounting ring over the flange. Attach the upper mounting assembly to the flange, sliding the snap ring onto the flange. When it pops into the groove, the snap ring is tight. Tighten the mounting screws until a tight seal is formed.

Run a drain pipe from your dishwasher to the disposal unit. In most cases, you must remove the drain plug from the dishwasher nipple before fitting the pipe. Apply plumber's putty before affixing the drain pipe. Attach the discharge tube to the disposal unit.

Lift the disposal unit into the mounting assembly, rotating the lower mounting ring over the top of the unit until the mounting tabs lock in place. Use a wrench or a screwdriver to tighten the mounting ring.

Rotate the disposal unit until the discharge tube faces the drain trap. Reconnect the waste line. In some cases, you will need to replace the waste line assembly to accommodate the discharge tube. Use plumber's putty to seal each connection. Plug the disposal power cord into the GFCI outlet. Turn on the power to the circuit and test the disposal.