How to Select and Install a Garbage Disposal 02:14

Find out how to select a replacement model and installing a new one.

Photo by: Wade Works Creative

Wade Works Creative

Step 1

Remove Existing Assembly

Remove all parts of the disposer kit from the box, and organize the contents. Remove the P-trap and existing drain basket assembly carefully from the sink (Images 1 and 2). Place a large pan below the sink to catch water that might spill when you disconnect the drain, and keep a towel close by to clean up spills.

Step 2

Prep for Assembly

If the new flange assembly is pre-assembled, remove the ring and loosen various fasteners to prepare for installation (Images 1 and 2).

Step 3

Apply Putty

Locate the flange gasket. Some kits will come with a rubber gasket, but using plumber’s putty will give your seal a longer life. Roll the putty into a snake shape approximately 3/8” in diameter and long enough to wrap around the gasket under the flange (Image 1). Press the putty evenly around the underside of the flange using your fingers as you would along the edge of a pie crust (Image 2).

Step 4

Photo by: Wade Works Creative

Wade Works Creative

Clean the Sink

Clean the sink well, especially around the drain opening.

Step 5

Attach Fastening System

Insert the flange on the top side of the sink, and attach the fastening system on the underside (Image 1). It is helpful to apply pressure on the flange from above using a second set of hands or a heavy object. This will keep the flange in place while attaching the fastening system below. Make sure the plumber’s putty is visibly oozing beyond the edge of the flange all around (Image 2). Remove the excess putty with a rag once a complete seal has formed.

Step 6

Attach Mounting Plate

Attach the mounting plate to the underside of the sink (Image 1). Fasten the screws, but be careful not to over-tighten them (Image 2).

Step 7

Photo by: Wade Works Creative

Wade Works Creative

Secure Tailpipe

Attach the tailpipe to the rubber seal on the side of the disposer unit, and secure it with a metal spring ring (Some units have a metal bracket to attach the tailpipe).

Step 8

Remove Breakout Plate

If you plan to drain your automatic dishwasher through your disposer, locate the breakout plate inside the inlet port (Image 1). Remove it by gently punching it with a screwdriver and hammer (Image 2). If you will not use your unit to drain a dishwasher, leave the breakout plate intact.

Step 9

Connect Wiring

Some disposer units do not come with a power cord attached. If this is the case, remove the plate with a screwdriver to access the electrical wiring (Image 1). Be sure to purchase a wiring kit with the proper power rating and hardware for your disposer unit (Images 2 and 3). When you connect the wiring harness to the disposer, ensure the cord is long enough to reach the receptacle without stretching the cord.

Step 10

Photo by: Wade Works Creative

Wade Works Creative

Attach Disposer Unit

Align the rubber seal ring on the top of the disposer with the flange beneath the sink. Press it into place, and loosely secure it by rotating the lower mounting ring onto the ramp tabs of the upper mounting ring. Rotate disposer unit as needed to align drain assembly.

Pro Tip

The disposer unit is heavy and can be awkward to maneuver beneath the sink. Use a large bowl or other sturdy object to prop up the unit as you position it.

Step 11

Connect Disposer to P-Trap

Use a hack saw or PVC cutter to trim the PVC extender pipe (Image 1), and connect disposer to the P-trap (Image 2).

Step 12

Photo by: Wade Works Creative

Wade Works Creative

Secure Unit

Now that the drain is assembled, rotate the lower mounting ring until all three mounting tabs are locked over the ridges in the slide-up ramps. Tighten with a screwdriver.

Step 13

Photo by: Wade Works Creative

Wade Works Creative

Make Sure Unit is Secure

Test for water tightness by plugging the drain with the stopper and filling the sink with an inch of water. Check for leaks under the sink to confirm that your plumber’s putty is making a good seal. Remove the drain stopper, and allow the drain and P-trap to fill with water. Check for leaks and tighten as necessary. Plug unit into a GFCI-protected receptacle, and organize cords as desired.