Whether your current garbage disposal is on the fritz or simply lacks the oomph you need to make your kitchen a perfect place, you're in luck. Replacing a garbage disposal is a simple, do-it-yourself project that you can complete in an hour or so. You'll go from a not working or low-performing unit to a high-powered, brand-new disposal in your kitchen in no time at all!
As a note, this guide will help you replace a garbage disposal that has a traditional plug for power. There are only four steps to remove and old disposal unit and seven steps to install a new one. It really is that simple.
Tools you'll need: Hammer, adjustable crescent wrench, phillips or flathead screwdriver, wooden dowel or steel punch, plumber's putty (if installing a new drain flange).
Removing Your Old Garbage Disposal
Step 1: Turn off the electricity
Find your breaker box and cut the circuit breaker that provides power to the plug that your disposal plugs into under your sink. This is for your safety as well as safety of your new unit. This will also ensure that power to your dishwasher is off if you have a dishwasher.
Step 2: Disconnect the drain tube
Use a wrench to disconnect the drain line where it connects to the disposal discharge tube.
Step 3: Loosen the fastening hardware
Your current garbage disposal will have bolts connecting your drain to the top of the garbage disposal unit. Loosen these using a screwdriver.
Step 4: If you have a dishwasher, remove the discharge hose
Next, if you have a dishwasher, you'll need to loosen the clamp that connects the dishwasher discharge hose to the disposal unit. Just use your screwdriver for this as well.
Step 5: Remove the old disposal unit
Note: You'll either need a second set of hands or want to prop a box under the unit to support it when it comes loose from the drain.
Locate the 3-tab ring where the top of your old disposal unit joins with the drain. Using either your hands or a screwdriver inserted into one of the 3 tabs, rotate the ring counterclockwise until the old unit releases from the drain. Voila! Your old garbage disposal has been removed. You're now ready to install your new garbage disposal.
Installing Your New Garbage Disposal
Step 1: Determine if you need a new drain assembly
When you replace a garbage disposal you might be able to use the drain assembly that's already installed from your previous unit. If that's the case, excellent!
If you need to replace the drain assembly, remove the current assembly and then clean the sink surface thoroughly. Make sure it's dry. Then, apply a 1/2" thick band of plumber's putty around the ring and press into place.
Now, place the new drain assembly into the sink, centering it in the drain opening. To make a tight seal, place the new garbage disposal unit on top of the drain assembly to press it into place while you continue working.
Step 2: Take apart the mounting assembly
Before you begin this step, be sure to take note of the order the pieces go in on the mounting assembly. We recommend placing them on the floor in the order you took them off to make sure you put them all back in the right order.
First, you'll take the mounting assembly off your new disposal unit. To do this, turn the LOWER mounting ring clockwise. This is the ring with the 3 tabs on it that looks just like the one you turned counterclockwise on your old unit in step 4 above. This will let you remove the sink flange assembly.
Next, you'll loosen the screws on the UPPER mounting ring. As seen in the picture above, the screwdriver will loosen the three screws. You won't remove the screws completely. You'll just loosen them.
Then, you'll remove the snap ring. Use a flathead screwdriver to remove the snap ring by sliding the blade under the ring and lifting. See the top of the cooresponding image.
Now, as you see in the lower part of the image above, you'll remove the mounting ring (the ring with the 3 screws in it) backup flange (shaped like a flower), and fiber gasket (the circular ring right above the flower-shaped ring) from the sink flange. Be sure to lay out these parts in the order you remove them so you can replace them in the right order. Feel free to snap a pic with your phone for reference, too! You can always refer back to the image above or your picture if you think you might have gotten a part out of order.
Step 3: Reassemble the mounting assembly
For this step, you'll be working under the sink. Grab a flashlight so you have plenty of light (you can even use the one on your phone).
Place the fiber gasket (first, closest to the sink), backup flange (second), and mounting ring (third, closest to the floor) onto the sink flange. The cooresponding image will help you make sure you have the pieces in the right order.
Now, you'll replace the snap ring to hold everything in place.
While you hold the 3 pieces up against the drain flange, open the snap ring and press it into the groove on the sink flange.
The final step is to tighten those three screws on the mounting ring. Be sure to not over tighten them and tighten each one evenly.
Now—you're almost there. Just a few more steps and your replacement garbage disposal will be up and running.
Step 4: Install the new discharge elbow
This is the step that gets the waste out of your disposal unit and sent down the drain, so this is important. You don't want to re-use your old discharge elbow, either. Be sure to use the new one included with your new unit.
Make sure the rubber gasket is on the discharge elbow and slide it all the way to the end that will connect to the disposal unit.
Then, locate the mounting flange (shaped like a diamond with a circular hole in the middle). Slide the mounting flange up over the discharge elbow and insert the discharge elbow into the unit, lining up the mounting holes with the holes on the side of the disposal unit. Attach the discharge elbow to the unit by tightening the screw on each side. Make sure the screws are tightened evenly and firmly, but don't over tighten. Refer to the image above.
If you don't have a dishwasher, you can skip step 5 and go straight to step 6.
Step 5: Knock out the dishwasher discharge plug (only if you have a dishwasher)
If you have a dishwasher, you'll need to install the discharge hose on your new garbage disposal unit. To do this, you'll need to knock out the plug that is factory-installed in your new disposal unit.
Insert a blunt object (like a steel punch or wooden dowel—do not use a screwdriver) into the plug and knock it out using a hammer. Use kitchen tongs or pliers to reach into the disposal and retrieve the plug. Throw the plug away.
Step 6: Connect your new garbage disposal to the mounting assembly
You're almost there! Nice work.
From under the sink, align the newly installed discharge elbow on the side of your new disposal unit with the piping. Raise the new disposal unit up into the mounting ring.
Next, locate the lower mounting ring (the one with the three tabs). Align the lower mounting ring with the ramps on the mounting ring extending down from under the drain. Turn the lower mounting ring clockwise until tight.
Then, grab a flathead screwdriver and insert it into one of the tabs on the lower mounting ring. This will give you the extra leverage you need to finish turning the lower mounting ring to lock it securely in place. Refer to the left side of the image below. The right side of the image shows how you can lock the lower mounting ring securely in place by using channel lock pliers instead of a screwdriver.
Step 7: Connect the discharge elbow to the piping
See the cooresponding image for reference.
Be sure to tighten the connecters properly. Some will allow you to hand-tighten and others will require that you use a wrench to establish a secure seal.
Now, if you don't have a dishwasher, you're all done! Your new garbage disposal unit is ready to go. Before you turn the unit on, run water to make sure all of your seals are tight.
Then, simply head to your breaker box, turn the power back on, and then plug your unit into the outlet underneath your sink.
Step 8: Attach the dishwasher discharge hose (only if you have a dishwasher)
As a reminder, this step is only if you have a dishwasher.
Connect the dishwasher drain hose that was attached to your old disposal unit to your new disposal unit. This will attach to the place where you knocked out the plug.
Slide the metal clamp on the dishwasher discharge hose to the attachment point on the replacement garbage disposal unit and tighten the clamp using a screwdriver.
Now, for you dishwasher owners, your replacement garbage disposal installation is complete! Before turning the power back on, run water into the sink to make sure everything is seated properly and your seals are tight. Then, flip your circuit breaker back on, plug your disposal unit in, and test the unit.
Congrats on replacing a garbage disposal! With the included video and step-by-step DIY guide, you'll be a home improvement pro in no time. Enjoy your spruced-up kitchen!