Lowe's Home Improvement

Install a Garbage Disposal

Installing a garbage disposal is a relatively easy project for an experienced do-it-yourselfer. Grab a few basic tools and follow our how-to.

Tools & Materials

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Working Safely

install a garbage disposal system

Before you begin your project, check with local authorities to see if a permit is required. It's also important to take a few safety precautions:

1.    Wear goggles and a dust mask.

2.    Turn off the power.

3.    Test the wires to ensure the power is off.

4.    Lock the panel box, so no one can accidentally turn the power back on while you're working.

5.    Have your work checked by an inspector.

6.    Consult a licensed electrician to avoid overloading the circuit.

Watch our DIY Basics Videos:

How Do I Strip a Wire?

How Do I Connect Two Wires?

Installing Your Garbage Disposal

Step 1

remove existing strainer

If you have a two-bowl sink, remove the drain lines that connect the two bowls. Remove the strainer from the bowl to which you'll be attaching the disposer. Then remove the strainer body, which forms the rim to which the drain line was attached. Once complete, a simple hole remains in the bottom of the sink bowl.

Step 2

install a garbage disposal

Roll plumbers putty between your hands to form a snake, runing it around the base of the disposer flange included with the unit. Place the flange in the drain hole, seating it firmly.

Step 3

install a garbage disposal

Install the gasket and upper- and lower-mounting rings on the flange. Then, snap the retaining ring in place. Tighten the three screws on the lower-mounting ring until the flange is firmly seated. Most of the plumber's putty will have squeezed from around the top of the flange at this point. Trim the putty and clean the sink.

Step 4

install your garbage disposal per manufacturer's instructions

Attach the disposer unit to the flange according to the manufacturer's directions. (Some are attached using a mounting ring. Others are attached with bolts.)

Step 5

install garbage disposal discharge tube

Using the included washer or gasket, attach the discharge tube to the discharge opening in the side of the unit. If a dishwasher is to be attached to the unit, knock out the plug inside the dishwasher nipple with a screwdriver. Clamp the dishwasher discharge tube in place on the nipple.

Step 6

install garbage disposal drain lines

Install the drain lines. If you have a two-bowl sink, both bowls can be routed through a single P-trap by running the discharge tube from the disposer to a T in the drain line above the trap.

Connect Electricity to the Garbage Disposal

Ideally, the disposer should have a dedicated circuit. If this is impossible or impractical, and you already have a dishwasher in place, you may be able to tie into the dishwasher circuit.

The switch necessary to operate the unit is a simple single-pole switch. The white wires are tied together with an appropriate wire nut, as are the bare ground wires. The black wires are each attached to a terminal on the switch—the incoming wire is attached to the bottom terminal, and the wire that travels to the disposer unit, is attached to the top terminal.

If you're using an existing switched circuit, or if you've had an electrician install one for you, the electrical connections necessary to install the disposal are minimal. At the disposal, remove the plate that covers the electrical connections for the unit. Using an appropriate wire nut, connect the white wire from the disposer unit to the white wire from the switch. Do the same with the black wires, and then connect the bare ground wire from the switch to the ground connector on the disposer. Replace the cover plate.