How to Install a Garbage Disposal

Basic steps on how to install a garbage disposal.

How to install a garbage disposal or replace a garbage disposal are basically the very same procedure and the basic steps to do either job are listed in this article.

The very first step and one of the most important is to make sure you have disconnected the power going to the garbage disposal. At this point before you have removed anything take a good at the new unit and make sure it will fit.

Next step is to remove all the drain lines that are attached to the current unit.

You will see a large nut that is on the base of the sink flange. Loosen this nut and let this nut drop down. Then push the sink strainer body up through the sink and remove it for now. Keep the strainer because you will have to reinstall it later.

It is very important that you take a putty knife and clean all the plumbers putty away from the sink strainer opening. Make sure the opening is completely clean.

Turn over the sink strainer and mounting assembly that you removed earlier and use a screwdriver to remove all the mounting screws and you should have access to the snap ring. Then remove the snap ring. You will probably need a screwdriver to pry off the ring off the sink flange. After you have removed the snap ring the mounting assembly should now come apart and you are now ready to install the new garbage disposal.

You will need plumber’s putty at this point and if you do not have any you can purchase at most any hardware store. Place a good amount of the putty around the strainer opening in your sink that you cleaned earlier. Slip the fiber gasket and the metal back up ring that you removed  earlier back over the sink flange. Replace the snap ring.

Now it is time to reinstall the mounting assembly onto the sink flange by replacing the screws you took out earlier and then setting the assembly down into hole in the sink where you placed the plumber’s putty. Go to the underside of the sink and replace and tighten the large nut that holds the assembly in place. Clean up any plumber’s putty on the top and bottom of the sink that oozed out when you tighten the nut.

On some garbage disposals there is a plug that will have to be knocked out and retrieved before you can install it on the mounting assembly. Check your owner’s manual and see if this applies to your unit. If you have an access issue this may be the best time to make your electrical connections to the unit. If you would prefer not to handle the electrical connection yourself, call in a licensed electrician because this must be done according to the electrical codes that are in place for your area.

LIft the disposal up onto the mounting assembly you installed on your sink and tighten the mounting tabs securely. Make sure you installed the gasket on top of the unit before you install it to the mounting assembly. Replace and tighten all the drain lines and the p trap to the unit.

You should now be ready to turn your garbage disposal on and test for a smooth operation with correct drainage and no leaks.  These are the basic steps on how to install a garbage disposal.


For more information on how to install a garbage disposal watch the video above by Lowes.