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How to Install a Garbage Disposal

by Paul Sanders

Stainless steel garbage disposal drain

Things You Need:

  • Garbage disposal
  • Plumber's putty
  • Wire nuts
  • Screwdriver

Some appliance upgrades can make a big difference but remain totally unseen, like a garbage disposal. Either as part of a remodel of an older home or replacing your existing sink disposal, a new disposal can help keep kitchen plumbing clear and make food preparation simpler. Here are some simple instructions for installing the garbage disposal yourself.

Installing a Garbage Disposal:

  1. Remove the old disposal. Garbage disposals connect to one or more drains on your sink as well as the waste pipes below the sink. You'll need to disconnect everything.

  2. Disconnect the waste pipes from the bottom and side of the garbage disposal.

  3. Unlock the garbage disposal from the sink drain by rotating the mounting bracket counter-clockwise around the top of the disposal. Then rotate the disposal itself and pull it away from the drain.

  4. After turning off power to the disposal at the circuit breaker, remove the metal plate at the bottom of the disposal and disconnect the electrical wiring, including the ground wire.

  5. Remove the old mounting bracket from the sink hole and scrape off any remaining plumber's putty, wiping the hole clean.

  6. Install the new mounting hardware. You may need to remove the new mounting bracket from the new garbage disposal, similar to the way you disconnected the old disposal from its mount.

  7. Separate the mounting bracket from the sink's drain plug. Then apply a 0.25-inch bead of plumber's putty around the new drain plug and press it firmly into the sink hole.

  8. Attach a washer and the new garbage disposal's mounting bracket from underneath the sink, exactly as it was assembled before you popped the old plug out. Then screw the mounting bracket back together.

  9. Wire the garbage disposal. Similar to the old disposal, you can remove the plate on the bottom of the new garbage disposal to work on the wiring.

  10. Thread the wires through the hole on the bottom of the garbage disposal and out from behind the plate.

  11. Attach the black and white wires with wire nuts. Then attach the ground wire to the grounding screw behind the plate. Replace the bottom plate.

  12. Mount the disposal to the sink. Just as you detached the old sink disposal, you'll now attach the new garbage disposal to the mounting bracket under the sink hole. Be sure that the waste drain port on the disposal is pointed toward the side of the sink where the drain pipes are located.

  13. Attach the waste pipes. You can clean out and use the old waste pipes or you can install new ones.

  14. Hand-tighten the P-trap to the bottom of the garbage disposal.

  15. Connect the drain pipe from the from the second sink drain into the side port on the garbage disposal using a flange to create an airtight seal.

  16. Test the disposal. Clean up any excess plumber's putty around the drain and turn the electricity back on. Run cold water and test your disposal. Check the pipe connections for leaks as well.

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