How to Install a Garbage Disposal

An In-Depth Guide to Successfully Installing a New Garbage Disposal in Your Home

Installing a new garbage disposal is a straightforward home improvement project that can make your life easier by freeing up space in your trash cans. With some basic tools and a bit of plumbing knowledge, you can have a shiny new garbage disposal up and running in no time. This step-by-step guide will walk you through the entire process, from choosing the right model to connecting it to your sink’s plumbing. We’ll cover garbage disposal installation from start to finish, including helpful tips and precautions along the way. Let’s get started!

Selecting the Right Garbage Disposal Model

The first step in installing a new garbage disposal is choosing the right model for your needs. Here are some things to consider:

Sink Type: Does your sink have a double basin or a single basin? Double basin sinks require a garbage disposal designed specifically for them.
Horsepower: More powerful motors (higher horsepower) will be able to grind up food waste more quickly and efficiently. Look for at least 1/2 HP.
Batch Feed or Continuous Feed: Batch feed models start up when a stopper is inserted in the drain. Continuous feed disposals operate using a wall switch.
Noise Level: Check decibel ratings if sound is a concern. Some disposals are designed to operate more quietly.
Grind Stages: Two-stage grinders pulverize food waste more thoroughly. This leads to better drain flow.
Warranty: Many quality garbage disposals come with at least a 5-year warranty. This protects against defects.

For most households, a continuous feed disposal with 1/2 to 3/4 HP and a corrosion-resistant stainless steel grinding chamber will be the best choice. Trusted brands like Waste King, InSinkErator, and GE offer great options.

How to Install a Garbage Disposal

Gather the Necessary Tools and Materials

Installing a garbage disposal requires some basic DIY tools and materials. Be sure you have the following on hand before getting started:

Garbage disposal: The specific unit you selected for purchase.
Plumber’s putty: For creating watertight seals.
Phillips head screwdriver: For tightening screws.
Wire stripper: For exposing the ends of electrical wires.
Wire nuts: For joining wires together.
Safety glasses and work gloves: For eye and hand protection.
Flashlight: For seeing inside cabinet space.
Trim trap: For diverting waste into the garbage disposal.
Extension cord: To test the disposal before permanent wiring.
Cable or zip ties: For bundling wires together neatly.
Rags, bucket, and sponge: For cleaning up.
Plumbing parts: Flange, gasket, drain elbow, and P-trap may be needed.

Being prepared with all materials and tools needed will make the installation process smoother.

Turn Off Power and Water Supply Lines

Before beginning installation, you must turn off the power and water supply to the sink. This important safety step prevents shocks or water damage.

First, locate the circuit breaker for the garbage disposal. Usually it is on the same circuit as the dishwasher or sink. Turn off the breaker switch.

Next, turn off the shut-off valves under the sink for both hot and cold water lines. These allow you to work safely without water spraying out of pipes.

Test that the power and water are fully disconnected by running the sink and turning on the switch for the disposal (if already installed). There should be no power or water flow present.

Disconnect and Remove the Existing Disposal

If there is already a garbage disposal connected to the sink, the first step is disconnecting and removing it. Start by:

Unplugging the cord or disconnecting the electrical wires. Be sure wires are safely capped off.
Detaching the drain pipe from the bottom of the disposal. Empty any remaining contents.
Removing the snap ring inside the sink flange that holds the garbage disposal in place. Use a flathead screwdriver.
Lifting the disposal out from the sink flange. Be prepared for some water spillage.

Now the sink is ready for the new garbage disposal installation. Inspect the flange for any cracks, damage, or need to replace the plumber’s putty.

Prepare the New Garbage Disposal

With the old unit removed, unpack the new garbage disposal. Follow these tips for proper preparation:

Clear out any packing materials or debris inside the disposal chamber.
Remove the mounting ring from the bottom of the unit. The rest of the disposal can remain attached to the sink flange.
Read the manufacturer’s instructions thoroughly. Make sure to follow any directions specific to your model.
Have the necessary plumbing parts ready, such as a drain elbow and discharge tube, and P-trap. These connect the disposal to the sink drain.
Inspect the pre-installed wiring (if any) and prepare electrical connections. More details on wiring are in the next steps.
Lubricate the grinding components following the product directions. This ensures smooth operation.
Check that the disposal flange fully covers the sink opening. Trim if needed.

Now the new garbage disposal should be test fitted into the sink drain opening to check alignment and positioning before permanent mounting.

Mount the Garbage Disposal in the Sink Flange

With the sink flange prepped, you’re ready to mount the new garbage disposal unit. Here’s how:

Apply plumber’s putty around the flange to form a seal between the disposal and sink. This prevents leaks.
Lower the disposal into the flange opening and press firmly in place. The unit’s weight should hold it.
Re-attach the snap ring around the flange to secure the garbage disposal. Tighten the screws evenly.
Use a rag to wipe away any excess plumber’s putty squeezed out around the flange.
Connect the mounting ring to the bottom of the disposal, lining up any tabs or notches.
Tighten the mounting ring bolts using an alternating pattern to ensure even pressure.
Tug downward on the disposal to confirm it is fully secured and unable to detach from the mounting assembly.

Connect Drainage Piping to Garbage Disposal

Now that the garbage disposal is securely affixed under the sink, it’s time to connect the drain piping. This carries waste from the disposal unit into your drain/vent system.

Attach the discharge tube piece (provided with the disposal) to the unit’s drain exit using the flange, gasket, and screws.
Connect P-trap piping from the discharge tube to the sink drain tailpiece. The P-trap retains water to prevent sewer gas from entering.
Use slip-joint compression fittings to connect pipes. Hand-tighten and then finish 1/4 turn with tongue-and-groove pliers.
Install a dishwasher drain connector (if needed) by tapping into the P-trap or disposal discharge.
Check all joints and connections for leaks and tighten or apply sealant if needed.
Cut any extra length off the end of the drain pipe to maintain proper slope and waste flow.

With drainage pipes securely installed, turn on the water supply and check underneath for leaks. Tighten any problem connections. Turn the water back off when done.

Wire the Garbage Disposal Electrical Connections

All garbage disposals require an electrical power source to operate the grinding motor. There are a few ways to handle wiring.

Hardwiring the Disposal

For a direct hardwired connection:

Shut off electrical power at the circuit breaker. Verify it is off.
Detach the cover plate beneath the disposal to access wiring.
Connect the disposal wires (usually black, white, green) to their matching household wires using wire nuts.
Ground the unit by connecting the green wire to the sink tailpipe with a grounded (jumper) wire.
Reattach the electrical cover plate when wiring is complete.

Using a Power Cord

For a plug-in cord connection:

Purchase a compatible 3-prong power cord. Match the rating to your disposal’s electrical needs.
Cut the appropriate-sized opening in the bottom cabinet wall to feed the cord through. Avoid pipe locations.
Plug the cord into the base of the disposal according to the manufacturer’s instructions.
Plug the cord into a ground fault circuit interrupter (GFCI) outlet for protection. Do not use an extension cord.

Testing the Connection

Once wired, preventing shocking is critical. To test:

Restore electrical power and verify that any outlet used is GFCI protected.
Use a non-contact voltage tester to confirm power to the disposal before touching any wires.
With the sink empty, run the disposal to check that the grinding plate turns freely. Listen for rattling sounds which could indicate an object obstruction.
Unplug power or flip off the breaker once you’ve confirmed proper operation.

Complete the Installation

You’re in the home stretch! Finish up your garbage disposal installation:

Reattach the P-trap and drain piping under the sink. Ensure a secure fit.
Turn on the water supply and check for leaks. Tighten any fittings as needed.
Run a full sink of water and test the disposal to confirm adequate drainage and no leakage.
Plug in power cord or turn on the circuit breaker to restore electrical supply.
Read instruction manual for any model-specific information such as resetting overload protectors.
Run disposal and flush with cold water for 1-2 minutes to check for vibrations, jams, or other issues.
Add dish soap and run again to eliminate odors from oil left over from manufacturing.

When protected from leaks, shocks, and jams, you’ll be all set to grind up food waste!

How to Install a Garbage Disposal

Troubleshooting Problems with a New Garbage Disposal

During or after installation, a new garbage disposal may occasionally run into issues. Here are some common problems and solutions:

Disposal hums but won’t run? The unit may need to be reset after an overload or jam. Press the reset button on the bottom (may require an Allen wrench) until the clicking stops.

Leaking from the drain pipe joints? Tighten the slip-nut connections with tongue-and-groove pliers. Apply additional P-trap sealant if needed.

No power? Double check that the wall switch is on and circuit breaker hasn’t tripped. Test or replace the unit’s overload protector.

Loud grinding noise? Turn off power and manually spin the flywheel plate. If it doesn’t spin freely, there may be an obstruction. Unjam the unit.

Drainage backing up? Clogged impellers could be slowing the waste flow. Use an Allen wrench to detach and clean the impellers. Avoid grease buildup.

Smelly odors? Run lemon rinds and baking soda down the disposal to deodorize. Check for and clear any food debris in the drain lines.

Leaking from mounting ring? Tighten the bolts evenly using an alternating pattern. Replace the flange gasket if it is worn out.

Continues tripping GFCI outlet? There could be a short in the wiring. Inspect cords and connections. Use a multimeter to test for electrical issues.

Still having trouble after trying basic fixes? Call in a professional plumber for garbage disposal service and repairs.

How to Install a Garbage Disposal

Maintaining Your Garbage Disposal

Installing your garbage disposal is only the first step to keeping your kitchen running smoothly. Regular maintenance will prevent problems and keep food waste grinding efficiently for years to come.

Here are useful tips for garbage disposal maintenance:

Run cold water through the disposal when grinding food waste. This hardens fats and greases, helping move them through the system.
Grind citrus fruit peels to help deodorize and freshen the drain. Citric acid cleans disposal walls.
Use baking soda and vinegar monthly to purge odors. Let the mixture foam in the disposal to clean the interior.
Avoid pushing dense or fibrous waste into the disposal like eggshells, corn husks, or coffee grounds. They can get clogged and cause jams.
Detach and clean the splash guard regularly. Wipe out any gunk and grime that can collect.
Use a disposer cleaner monthly to clear grease and grime. Grind ice cubes to freshen.
Detach and inspect impellers for obstructions that reduce grinding capacity. Remove any debris.
Lubricate gears and shredder ring per manufacturer instructions to prevent rust and improve performance.
Confirm adequate sink drainage to avoid standing water in the disposal side of a double basin sink.

With occasional cleaning and maintenance, your garbage disposal should run smoothly for years. Call a plumber if repairs are ever needed.

How to Install a Garbage Disposal

Frequently Asked Questions About Installing Garbage Disposals

Looking to install a new garbage disposal? Here are answers to some frequently asked questions:

How difficult is it to install a garbage disposal?

Garbage disposal installation is considered an intermediate DIY project in terms of difficulty. With some basic plumbing and electrical knowledge, the average homeowner can handle it. Pay close attention to instructions and safety.

Can I install a garbage disposal myself?

If you know how to use common tools and have a general understanding of plumbing and electrical systems, you can self-install a garbage disposal. Make sure to turn off water and power to the sink first. Consider asking a plumber friend for advice.

What skills do I need to install a garbage disposal?

Handy skills like turning wrenches, stripping wires, and applying sealant are needed. Comfort shutting off water lines, connecting drains, and utilizing power tools is important. Prior plumbing or electrical experience is very helpful.

How long does it take to install a garbage disposal?

The installation process takes 2-3 hours on average, with more time needed for attaching wiring or adjusting plumbing. Allow extra time if this is your first garbage disposal install. Proper prep work helps speed things along.

Should I hire a plumber to install a garbage disposal?

A professional plumber can complete garbage disposal installation in an hour or less. This avoids frustrations and potential safety risks of a DIY project. The cost averages $185-$250, but provides peace of mind.

Can I install a garbage disposal with a septic tank?

Yes, garbage disposals can usually be installed with septic tanks; however, the additional waste may require septic pumping more frequently. Consult a septic service company before installation. Use a higher horsepower disposal.

How much does it cost to install a garbage disposal?

If hiring a plumber, expect to pay $185-$250 for disposal installation. DIY installation averages $65-$150 for the garbage disposal unit itself, plus plumbing supplies. The project costs $100-$300 overall.

Conclusion

I hope this guide covers everything you need to know about successfully installing a new garbage disposal in your kitchen sink. With the right tools, safety precautions, and step-by-step process, you can upgrade your sink’s functionality quickly and affordably. Just be sure to do your research ahead of time and call in electrician or plumbing help if needed. Know the proper maintenance to keep your garbage disposal grinding smoothly for years. Your kitchen waste management will be much improved.