How to Replace a Garbage Disposal

Garbage disposals are the workhorses of the kitchen sink, but they inevitably reach a point where they hum, leak, or simply quit grinding. When yours stops clearing food scraps or starts spraying water into the cabinet below, it is time for a swap. A professional install looks seamless, with no leaks at the flange and minimal vibration during operation. Taking on this project saves a significant service fee, provided you respect the electrical and plumbing connections. The secret to a successful replacement is ensuring the new unit matches your existing flange size, which avoids the headache of prying out an old, caulked sink drain. Work slowly, keep a bucket handy for the residual water, and double-check your seals before the first test run.

  1. Kill the Power First. Turn off the circuit breaker for the disposal at the main panel. Clear out the cabinet under the sink and place a bucket or towel directly beneath the disposal unit to catch trapped water.
  2. Unhook the Old Unit. Loosen the metal clamp or nut connecting the drain pipe to the side of the disposal. Disconnect the dishwasher hose if it is attached, then unscrew the mounting ring to drop the unit from the sink flange.
  3. Clear the Old Seal. Loosen the three mounting screws on the old flange assembly, pry the snap ring off, and push the flange up through the sink. Clean the sink drain opening thoroughly with a putty knife to remove old plumber's putty.
  4. Seal and Seat Flange. Roll a rope of fresh plumber's putty and press it around the underside of the new sink flange. Press the flange firmly into the drain hole and tighten the mounting assembly from underneath the sink.
  5. Connect Power Safely. Remove the electrical cover plate from the bottom of the new unit. Connect the white wire to white, black to black, and ground to green using wire nuts, then secure the cable with a strain relief clamp.
  6. Lock and Test. Lift the new disposal into the mounting bracket and twist it until it locks securely. Reattach the drain pipe and dishwasher hose, ensuring all gaskets are seated properly before tightening the slip nuts.