Installing a Replacement 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, remove, and replace.



  • There is a correction to Installation, Care and Use Manuals included with products manufactured November 2019 to January 2020. There is an important update to step six of the manual. Please review the update by clicking here.

Watch & Learn

InSinkErator shows you how to install a 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

1. Turn off power to the garbage disposal and disconnect the down trap.

Turn off the electrical power at the fuse box or circuit breaker. Then, using adjustable pliers, disconnect the drain top from the garbage disposal waste discharge tube. (See Fig 1a)

install garbage disposal

2. Free the garbage disposal from the mounting assembly.

Support the garbage disposal with one hand and insert the end of the wrenchette or screwdriver into the right side of one mounting lug on the lower mounting ring. Lift the garbage disposal slightly and loosen the lower mounting ring by pushing or pulling the wrenchette or screwdriver to the left until the garbage disposal is free from the mounting assembly. (See Fig 1b)

install garbage disposal

3. Disconnect the electrical.

Lay the garbage disposal on its side and remove the electrical cover plate from the bottom. Loosen the green ground screw and remove wire connectors. Disconnect garbage disposal wires from electrical supply wires. Loosen screws on the electrical clamp connector and remove wires from the garbage disposal.

4. Remove existing mounting hardware if hardware replacement needed. Otherwise skip to step 12.

To remove the existing mounting hardware, loosen the three mounting screws, pry the snap ring off with a screwdriver and remove the old mounting assembly. (See Fig 2)

install garbage disposal mounting assembly

5. Remove the old sink flange and putty.

Push the old sink flange up through the sink hole. Use a screwdriver or putty knife to carefully scrape all old putty from the edge of the sink hole.

6. Install the new sink flange, gasket and rings.

Place a 1/2 inch 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 the garbage disposal, on top of the sink flange will help hold the sink flange in place while mounting the sink flange to the sink. To avoid scratching your sink or the flange, place a towel between the sink surface and the weight. (See Fig 4) From under the sink, slide the fiber gasket, backup flange and mounting flange over the sink flange. Hold these pieces in place.

install garbage disposal sink flange

7. 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.

8. 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.

9. 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. The garbage disposal will now hang by itself.

10. 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 7b)

install garbage disposal discharge tube

11. Align the discharge tube with the drain trap.

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 as necessary. If it is too short, you can purchase an extension.

12. Lock the garbage disposal in place.

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. Now that everything is installed and in position, lock the garbage disposal to the sink mounting assembly using the wrenchette that came with the unit. For Evolution models, insert the Quiet Collar® Sink Baffle into the sink opening by pressing it into the sink until it snaps into place. (See Fig 7c)

install garbage disposal plumbing

13. Test the garbage disposal.

For all models, you should test for leaks at the sink flange, dishwasher, tail-pipe and mounting assembly connections. Finally, turn on the electrical breaker to test its operation.

Looking for more?

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

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