How to Install a Garbage Disposer

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What You'll Need
­Pipe wrench
­­Worm gear clamp
Plumber's putty
­Phillips screwdriver
­Flathead screwdriver
­Dishwasher drain connector kit (Optional)
Copper wire
­Wire nuts (Two size 54)
­On-off electrical switch

Installing a food waste disposer (also known as garbage disposal) might seem daunting, but it is a straightforward task that can be completed in about 10 steps, outlined in the instructions below.

Be sure to first review the installation, care, and use manual that comes with your disposer for more detailed instructions. If you have a disposer manufactured by InSinkErator, you can visit for more information.

Step 1 - Remove P-trap

Disconnect the p-trap and the horizontal extension pipe using large channel-lock pliers or a pipe wrench to loosen the nuts that hold the pipes together. When both connections are free, remove the parts. Take the chance at this time to clean the horizontal drain pipe to eliminate any possible blockage that may have accumulated.

Step 2 - Take the Strainer Body Out

Remove the strainer body from the sink by unscrewing the large nut that holds it in place underneath the sink. Then, push the strainer body up through the sink hole to pull it out, and clean off the old plumber’s putty that surrounds the edge of the drain opening.

Step 3 - Attach Mounting Assembly

Separate the parts of the mounting assembly from the disposer. Then, loosen the screws of the mounting assembly, and remove the snap ring. Place a 1/4-inch bead of plumber´s putty around the drain opening in the sink, and drop the new sink flange into the drain opening and press it into place. From under the sink, slide the fiber gasket and backup ring onto the sleeve, holding these pieces in place. Finally, slip on the mounting ring and snap ring.

Step 4 - Secure Assembly in Place

Afterward, tighten the three mounting screws. Alternate 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 5 - Remove Dishwasher Knockout Plug

If you have a dishwasher, you will need to tap out the dishwasher knockout plug at this time. To do so, lay the disposal unit on its side and use a screwdriver and hammer to tap it out. Remember to remove the knockout plug from inside the disposer.

Step 6 - Connect Wiring

Lay the disposer on its side under the sink, so you can make the electrical connections. Before starting, check your local building codes, as they may require a licensed electrician to make these electrical connections. Also, be sure to turn off electrical power at the fuse box or circuit breaker before removing electrical cover plate. Disposer must be grounded as well. Improper grounding could result in electric shock, so if you are unsure the connection has been grounded properly, contact a certified electrical contractor.

Remove the plate on the bottom of the disposer to expose the wiring. Using wire nuts, connect the white wire from the disposer unit with the white wire from the power supply. Follow the same step to connect the black ones. Finally, connect the ground wire from the supply to the ground on the disposer unit, and replace the plate to cover the wires.

With that, your waste disposer is ready for use. Be sure to keep it clean and well-maintained, and it will be an invaluable tool in your kitchen for years to come.