• In this video, This Old House plumbing and heating expert Richard Trethewey explains how to install a garbage disposal.


    1 Turn off the electrical power to the garbage disposal; use tester to ensure power is off.
    2 Disconnect the electrical cable from the underside of the disposal.
    3 Unbolt the drainpipe from the side of disposal.
    4 Loosen locking ring and remove the old disposal.
    5 Unscrew the mounting ring from underside of sink.
    6 Remove the locking ring with a screwdriver.
    7 Push out the sink flange from the drain hole in sink; clean away old putty.
    8 Apply bead of plumber's putty around sink flange, then set it in drain hole.
    9 Reattach mounting ring to underside of sink; tighten the screws.
    10 Remove excess putty from around top of sink flange.
    11 Reconnect the electrical cable to the disposal.
    12 Attach the disposal to locking ring; tighten with screwdriver
    13 Connect the tailpiece and rubber gasket for the drain line to the disposal.
    • Difficulty: Easy to moderate
      Working in the cramped quarters beneath a sink can be uncomfortable, but you're not there for very long
Ask TOH users about Appliances

Contribute to This Story Below

      Video Directory

      Selected Topic/Section

      Tools List

      • Phillips screwdriver
        used to remove the old disposal unit, and install the new one
      • wrench
        Open-end wrench
        used to loosen and tighten hex-head mounting screws
      • electrical tester
        Electrical tester
        used to ensure the electrical power is off

      Shopping List

      1. Garbage disposal