How to Install a Waste Disposal

Clean out the area under your sink of all items to give yourself room to work. Remove the doors if necessary to gain adequate access.

Turn off the power to the sink/kitchen area, whether you're replacing an existing unit or installing a new assembly. Shut off the water supply.

Disconnect the existing unit and remove it. If you don't already have a garbage disposal, remove the drainpipe that connects the sink to the plumbing. This usually consists of disconnecting the "J" or "P" pipe from the sink drainpipe. Make sure to have a bucket or other receptacle available to catch waste water. Disconnect any dishwasher plumbing if you have any.

Remove the sink strainer by removing the large nut that holds it in place under the sink. You'll need large channel locks or a crescent wrench.

Remove the old strainer and clean the sink drain opening of any old putty. Use ammonia, turpentine or nail polish remover to break down the putty, scrub with a steel wool pad, and clean and rinse with soap and water. Dry thoroughly.

Place a bead of plumber's putty around the drain opening on the inside of the sink. Clear silicone can also be used.

Place the new strainer/flange into the drain opening and gently but firmly press it into place. You may want to place a heavy object, like a large pot filled with water, on top of the new flange to hold it in place while you're working underneath the sink.

Attach the upper mounting bracket onto the bottom of the flange. Gasket placement will vary from model to model, but make sure to install the gasket as directed. You may or may not have to slide the gasket and mounting (or "snap") ring into place.

Tighten the three mounting screws (they actually look more like long blots or rods). Tighten the screws alternately, as you would when tightening lug nuts on a car wheel.

Wire the disposal if you don't have an existing connection. Most disposals come equipped with a power cord; some don't, and you'll have to buy a two-ended cord that plugs into both the disposal and the outlet. You may need to wire --- or have wired --- an electrical connection to create an outlet box under the sink in which to plug the disposal. You also could wire the disposal directly to a power source by removing the electrical plate on the disposal and connecting the wires accordingly (black to black, for instance) and connecting the ground. (See References 1)

Pop out the dishwasher knock-out plug if you'll be connecting a dishwasher.

Align the disposal unit's "ears" with the mounting screws and slide it into place. Depending on the model, you'll probably have to turn the unit about three-quarters of a turn to lock it into place.

Tighten the mounting bracket nuts and lock the unit in place, usually with an Allen wrench that may be included with the disposal.

Connect the plumbing pipes. If you're replacing a disposal, the pipes should align. If it's a new unit, you'll probably have to add extensions or cut pipes to accommodate the disposal. If may simply be a matter of cutting existing pipe and re-locating the connecting collars.

Turn the water back on and run the faucet to check for leaks. Turn the power on, plug in the disposal and turn it on while running cold water to test the unit. Clean off any putty or silicone around the sink drain.