Installing a New Garbage Disposal

If you've just purchased a new InSinkErator garbage disposal, you'll be glad to know our garbage disposals are the easiest to install.

Watch & Learn

InSinkErator shows you how to install a new garbage disposal by following the steps outlined in the instructions manual and as shown in this 4-minute video.

Written Directions

Before attempting to install your garbage disposal, read and understand the entire InSinkErator safety and installation instructions included with your garbage disposal model.

Materials Needed

Plumber's Putty (.1 kg)
Wire Nuts (2-size 54)
Worm Gear Clamp
Dishwasher Drain Connector Kit (optional)
Channel-Lock Pliers
Flathead Screwdriver
Phillips Screwdriver
Pipe Wrench



  • The following instructions are for a first-time garbage disposal installation. If replacing a garbage disposal, click here for instructions.

1. Disconnect the p-trap and the horizontal extension pipe.

Large channel-lock pliers or a pipe wrench work well to loosen the nuts holding the pipes together. When both connections are free, remove the parts. You may want to clean the horizontal drain pipe to eliminate any possible blockage. (This is not necessary in new construction.)

2. Disconnect the down drainpipe.

Using large channel-lock pliers, disconnect the down drainpipe coming from the sink and the connection that attaches it to the p-trap. When both connections are free, remove the parts. (See Fig 1)

install garbage disposal

3. Unscrew the large nut.

Unscrew the large nut that holds the strainer in place underneath the sink. Remove the strainer body.

4. Pry off snap ring and clean off the old plumber's putty.

Using a flathead screwdriver, loosen the 3 screws on the mounting assembly and pry off the snap ring. Clean off the old plumber's putty that surrounds the edge of the drain opening.

5. Install the new sink flange.

Place a 1/2" rope of plumber's putty around the drain opening in the sink. Drop the new sink flange into the drain opening and press it into place. Placing a weight, such as your garbage disposal, on top of the sink flange will help hold the sink flange in place while mounting it to the sink. To avoid scratching your sink or the flange, place a towel between the sink surface and the weight. (See Fig 2)

install garbage disposal sink flange

6. Install gasket and flanges.

From under the sink, slide the fiber gasket, backup flange and mounting flange over the sink flange. Hold these pieces in place.

7. Slip on the mounting and snap rings.

Next, slip on the mounting ring and snap ring. Tighten the three mounting screws, alternately tightening each screw a few turns at a time until the mounting assembly is evenly and tightly seated against the bottom of the sink.

8. Remove the dishwasher knockout plug.

If using a dishwasher, you will need to tap out the dishwasher knockout plug. Lay the garbage disposal on its side and use a screwdriver and hammer to tap it out. Next, remove the loose knockout plug from inside the garbage disposal. (See Fig 3)

install garbage disposal to dishwasher

9. Connect the electrical.

Hardwired Unit:

Turn the garbage disposal over and remove electrical cover plate. Pull out wires. Insert cable connector (not included) and run electrical cable through access hole on bottom of garbage disposal. Tighten cable connector. Push wires into garbage disposal (do not displace cardboard shield) and replace electrical cover plate.

If you have a hardwired unit and you're looking to attach a cord, you will need a power cord kit. For power cord kit installation instructions, click here.

Corded Unit:

For a garbage disposal with a factory-installed cord, simply plug in to the outlet under your sink after completing the rest of the steps.

10. Hang the garbage disposal.

Hang the garbage disposal by aligning the three mounting tabs with the slide-up ramps on the mounting ring. Holding the garbage disposal in place, turn the lower mounting ring until all three tabs are locked into the mounting assembly. (See Fig 5a)

install garbage disposal

11. Insert the discharge tube.

Insert the discharge tube into the discharge coupler, then slide the clamp over the discharge tube and position it in the groove on the rubber tailpipe coupler. (See Fig 5b)

install garbage disposal

12. Align the discharge tube with drain pipe.

Rotate the garbage disposal so that the discharge tube is aligned with the drain trap. If the discharge tube is too long, cut off as much of the tube as necessary. If it is too short, you can purchase an extension. If you are connecting the garbage disposal to a dishwasher, it may be connected through an air gap. Use a hose clamp to attach the drain hose to the dishwasher inlet.

13. Lock the garbage disposal in place.

Now that everything is installed and in position, lock the garbage disposal to the sink mounting assembly using the wrench that came with the unit. Insert the Quiet Collar® Sink Baffle into the sink opening by pressing it into the sink until it snaps into place. (See Fig 5d)

install garbage disposal

14. Test the garbage disposal.

Test for leaks at the sink flange, dishwasher, tail-pipe and mounting assembly connections. Finally, turn on the electrical breaker to test its operation. Enjoy your new garbage disposal!

Looking for more?

Text us at 262-233-2231 for personalized help with installing your new InSinkErator garbage disposal! 

Was this answer helpful?

Need additional help? Contact Us