How to Install a Garbage Disposal

Lead Image for How to Install a Garbage Disposal
  • 1-3 hours
  • Beginner
  • 25-50
What You'll Need
Slotted screwdriver
Adjustable pliers
Plumber’s putty
Electrical tape
Wire connectors
Safety glasses
What You'll Need
Slotted screwdriver
Adjustable pliers
Plumber’s putty
Electrical tape
Wire connectors
Safety glasses

Note: Important safety information is provided in the manual that came with your new disposer. Please refer to individual product manuals for important installation variances between models. The steps described are only an installation overview for InSinkErator® Evolution Series models. Refer to for model-specific information, diagrams and manuals, and for more details regarding installation.

In general, you will be following this activity sequence: Make sure the circuit breaker on the main electrical panel is turned off. Disconnect the electrical and dishwasher connections. Remove the existing plumbing pieces that are connected to the drain opening. Then you can install the mounting bracket that will hold up the disposer. Next, make the electrical and dishwasher connections. Finally, you can mount the disposer and hook it up to the drain plumbing.

Step 1 - Turn Off the Electricity

Turn off the circuit breaker on the main electrical panel.

Step 2 - Disconnect the Appliances

Disconnect the electrical and dishwasher connections.

Step 3 - Remove Plumbing Connections

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

Step 4 - Clean the Drain Opening

Clean off the old plumber’s putty that surrounds the edge of the drain opening.

Step 5 - Mount the Sink Flange

Place a ½” bead of new 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 disposer, 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.

Step 6 - Hold the Flanges in Place

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

Step 7 - Attach the Mounting Hardware

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.

Step 8 - Remove the Dishwasher Knockout Plug

If using a dishwasher, you will need to tap out the dishwasher knockout plug. Lay the disposer on its side and use a screwdriver and hammer to tap it out. Next, remove the loose knockout plug from inside the disposer.

Step 9 - Connect the Electrical

Lay the disposer on its side under the sink so you can make the electrical connections. Again, make sure the circuit breaker is off. Remove the plate on the bottom of the disposer to expose the wiring and use wire nuts to connect the wires from the disposer to the matching wires for the power supply. Finally, secure the power cord to the bottom of the disposer using the proper connection. Replace the plate to cover the wires.

Step 10 - Hang the Disposer

All Evolution models install similarly. Hang the disposer by aligning the three mounting tabs with the slide-up ramps on the mounting ring. Holding the disposer in place, turn the lower mounting ring until all three tabs are locked into the mounting assembly. The disposer will now hang by itself.

Step 11 - Attach 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.

Step 12 - Attach the Drain Hose

Rotate the disposer 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's too short, you can purchase an extension. If you are connecting the disposer to a dishwasher, it may be connected through an air gap. Use a hose clamp to attach the drain hose to the dishwasher inlet.

Step 13 - Lock the Disposer in Place

Now that everything is installed and in position, lock the disposer to the sink mounting assembly using the special 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.

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.