Home Repair & Maintenance Ideas and Tips

Garbage Disposal 101: How to Install a Disposal

Your garbage disposal just died, and you don’t want to wait for a plumber to install a new one. No worries! Installing a garbage disposal yourself can be fairly easy. Completing this DIY task should take about an hour or two if you’re pretty handy — and only a bit longer if you’re not. Here’s everything you need to know before you start rolling up your sleeves and getting to work underneath your kitchen sink.

install garbage disposal

Tools and Materials You’ll Need to Install a Garbage Disposal

For this job, you'll need a combination of plumbing and electrical tools and materials.

  • Slotted (flat blade) screwdriver
  • Phillips head screwdriver
  • Adjustable wrench
  • Plumber’s putty
  • Circuit tester
  • Twist-on wire connectors
  • Electrical tape
  • New garbage disposal unit

Step-by-Step Instructions on How to Install a Garbage Disposal

  1. Turn off the power to your garbage disposal. Tape over the switch so no one turns it on accidentally while you are uninstalling your old unit and installing your new unit. Use your circuit tester to make sure no electricity is flowing to the unit. If so, disconnect the electrical cable from the underside of the garbage disposal. Detach the access hole cover using a Phillips head screwdriver. Pull out and disconnect the wires inside the access hole. Finally, disconnect the metal cable that acts as a ground for the system. 
  2. Unbolt the drainpipe from the side of the disposal. Use your adjustable wrench to remove the two nuts.  
  3. Loosen the locking ring and remove the disposal. Insert a slotted screwdriver into the lower mounting ring and turn it about one-fourth of a turn counterclockwise to unlock the disposal. The unit should drop from where it was attached to the mounting assembly, so keep a tight grip. 
  4. Fully unscrew the mounting ring from the underside of the sink. 
  5. Remove the locking ring with a screwdriver. 
  6. Push the sink flange up from the sink drain. Scrape away any old plumber's putty.
  7. Apply a generous amount of plumber’s putty around the flange to act as a gasket. Place the sink flange back in the drain hole.
  8. Reconnect the mounting ring, using a screwdriver to tighten the mounting screws. 
  9. Scrape away any excess putty around the sink flange both topside (in your sink basin) and underneath.
  10. Reconnect the electrical cables and ground wire before installing the garbage disposal. Remove the access hole cover on your new unit and retrieve the wires inside. Connect the two white wires (one from the garbage disposal, the other from the wall) using twist-on wire connectors. Then connect the colored wires (they may be black or blue). You can also use electrical tape to attach the wires to the twist-on connectors. Finally, hook up the ground wire. After you've made all the electrical connections, return the wires to the access hole and replace the cover.
  11. Attach the new disposal to the locking ring. Insert the mounting gasket into the mounting assembly. Turn the lower mounting rings clockwise until the mounting tabs feel secure and the disposal feels stable. 
  12. Connect the tailpiece and rubber gasket for your drain line to the disposal.
  13. Turn on the power to your disposal. You’re ready to grind.

When you’re using your new garbage disposal, be sure to scrape big pieces of food into the trash before using it, and never ask your unit to dispose of coffee grounds, vegetable peelings (especially potato skins), grease or oil. Otherwise, your kitchen drain may become clogged.

American Home Shield’s Systems Plan covers the repair or replacement of your garbage disposal, as well as many other systems, including electrical, plumbing, air conditioning and more. Contact us today to learn more about our plans and how we partner with trusted, expert contractors to make sure your home repairs are completed quickly and with minimal inconvenience to your household.

DIY tips are for informational purposes only. Learn more.