How to Install a Garbage Disposal Unit With a Dishwasher

Turn the kitchen power off at the breaker box. Label the breaker so that someone does not turn on the power while you are working. Disconnect the dishwasher drain from the sink drain using a pair of pliers to release the clamp. Disconnect the S-trap from the sink drain using a pipe wrench to turn the fitting counterclockwise.

Remove the existing tailpiece from the sink drain using the pipe wrench. Twist the retaining ring counterclockwise and remove the drain strainer. Spread plumber's putty on the bottom of the drain ring and install the disposal drain in the sink. Install the drain gasket and twist the retaining ring on by turning it clockwise until it is hand tight.

Connect the new tailpiece to the drain and secure it with the pipe wrench. Connect the P-trap from the drain kit to the tailpiece and tighten the fitting using the pipe wrench. Connect the P-trap to the drainpipe using a pipe wrench to tighten the fitting.

Install the electrical wiring for the new garbage disposal and connect it to the circuit. Install the power switch to the wall at the sink and connect it to the new wiring using a screwdriver. Connect the wires to the garbage disposal. White is neutral, black is the hot wire and green or bare is the ground wire.

Attach wire nuts to the exposed connections twisting them on until they are tight. Place the cover on the disposal wire box and tighten it with a screwdriver. Lift the disposal up to the drain and secure it by turning the retaining ring clockwise to tighten the fitting.

Insert a screwdriver into one of the loops to lock the ring, if necessary. Connect the long end of the P-trap to the garbage disposal and tighten the retaining screws using a screwdriver. Tap out the dishwasher plug in the garbage disposal using a screwdriver and a small hammer.

Connect the dishwasher drain to the disposal using a pair of pliers to open the hose clamp. Turn the power back on to the kitchen at the breaker box. Turn on the water in the sink and run it into the disposal unit. Turn the disposal switch on to test the installation.