Installing A Replacement Garbage Disposal

If your old garbage disposal has worn out, don't go without one. If you're the DIY homeowner type and plan to replace the unit with the same brand and model, you can do the installation yourself. If you're uncomfortable doing home plumbing repairs, contact one of your local plumbing services. They can show you the latest models and install a new unit quickly. But if you have some experience and a few simple tools, here are the steps to replace that old disposal unit.

Supplies You Will Need

  • flat-blade screwdriver
  • channel-lock pliers
  • bucket that fits under the sink
  • couple of old rags for cleanup

From the plumbing supply or home improvement store:

  • replacement garbage disposal
  • small container of plumber's putty

Removal of the Old Unit

  1. Turn off the switch to the garbage disposal at the circuit breaker box for the house.
  2. Turn off the water at the shutoff valve under the sink.
  3. Place the bucket under the disposal to catch any spills.
  4. Disconnect the drain pipe on the side of the disposal and set aside.
  5. Disconnect the drain from the dishwasher on the side of the disposal (if installed).
  6. Hold the disposal from the bottom and push up while turning counterclockwise to separate it from the mounting ring.
  7. Empty any water out of the disposal into the bucket, then turn it upside down on the floor.
  8. Remove the plate covering the electrical wires.
  9. Disconnect the green ground wire from the unit.
  10. Disconnect the white and black wires held together by the wire nut.
  11. Set the old garbage disposal unit aside.

Installing the New Unit

  1. Clean any sealer from the mounting ring under the sink.
  2. If the new unit came with a rubber gasket to seal against the mounting ring, slip it into place around the ring on the top of the unit. Otherwise, place a small amount of plumber's putty in the mounting ring hanging under the sink.
  3. Turn the new unit upside down on the floor within reach of the electrical wires under the sink.
  4. Remove the access plate to the connections on the unit.
  5. Secure the ground wire to the green screw on the unit.
  6. Twist together the two black wires, then the two white wires and secure with wiring nuts.
  7. Screw the access plate back onto the unit.
  8. Turn the unit over and lift it up to engage its mounting ring with the one hanging down from the sink.
  9. Turn the unit slightly clockwise until you feel the disposal click into place on the mounting ring.
  10. Make sure to turn the unit so the drains are accessible.
  11. Attach the drain pipe from the dishwasher to the unit.
  12. Attach the drain pipe from the kitchen drain to the unit.
  13. Turn the water on under the sink.
  14. Run the water for a few minutes while looking for leaks.
  15. Turn on the power at the circuit box and test the unit.

Problems That Require a Plumber's Help

  • If you want to install a different garbage disposal unit than what you now have, the mounting hardware will be different. The plumber will change out all of the mounting hardware to install the new unit.
  • If corrosion keeps you from disconnecting the old unit, have a plumber do the work. They will need to replace all of the mounting hardware, plus the rusty sink flange, so the new disposal can be installed.