Basic Garbage Disposal Plumbing

What You'll Need
Wire nuts
Electrical tape
Putty knife
Plumbers putty
Pipe wrench

Garbage disposal plumbing isn’t particularly complicated. Installing a garbage disposal is a job everyone can do and it will only take about an hour. In most instances, you can use the tools you already have in your workshop. However, you will need an outlet for the disposal under the sink.

Step 1 - Preparing the Sink

Start by cleaning out the cabinet under the sink. Using your wrench, disconnect the strainer from the sink. Put your bucket under the pipe and disconnect the “J” pipe, allowing it to empty into the bucket. Now, you’ll see a large nut holding the strainer in place. Loosen and remove it and then take out the strainer.

Step 2 - Mounting Rings

To put the garbage disposal in place, you’ll need to begin with the sink flange and the mounting assembly, which are the upper and lower mounting rings, along with the correct bolts to hold them in place.

Put a bead of plumber’s putty on the sink around the drain. After this, push the sink flange on top of it. Move under the sink and slide the upper mounting ring, complete with a gasket above it, onto the part of the flange which comes down from the sink. Use the snap ring to connect to the flange securely and connect the lower mounting ring and mounting bolts, tightening them securely.

Step 3 - Wiring

Turn the garbage disposal upside down and you should see a hole for the flywheel wrench, a red reset button and the cover plate for the electrical connection. Unscrew the cover plate to expose the three wires. One will be black, one white and one will either be green or bare copper.

The box for the garbage disposal will also include a plug and cord. Put the wiring together according to the manufacturer’s instructions.

Step 4 - Dishwasher Plumbing

Look on the side of the disposal for a small tube. This will have a metal cover. Knock it out with a hammer and screwdriver. If you don’t have a dishwasher, don’t remove this cover.

Step 5 - Disposal Mount

Line the disposal up with the mounts. Slide the flanges on the disposal into the mounts and turn until the garbage disposal locks into place.

Step 6 - Plumbing

For garbage disposal plumbing, start by connecting the drain line from the dishwasher to the side of the disposal. Put a clamp over the hose and tighten it down on the metal so the connection is secure and watertight. A Champion clamp will work well for this. For the drain, be prepared to cut plastic pipe so the “J” trap fits properly under the disposal. You’ll need to use nylon washers on each lock nut by sliding the lock nut on first, and then applying the washer.

Connect up all the drainage pipes and attach to the drain of the disposal. This is attached with a rotating ram collar. You need to tighten this down with a screwdriver or wrench, locking the disposal into place. Check for any leaks in the garbage disposal plumbing by turning on the cold water and visually checking to see if water comes from any of the connections. Turn on the dishwasher and check that connection as well. Finally, plug the disposal in and turn it on, making sure the water is still running.