When the old garbage disposal finally gives up the ghost, the cost of hiring a plumber to replace it can make many homeowners just do without for a while. With a little bit of know-how, though, it’s not difficult to replace, and you can easily save more than half the cost by doing it yourself.
Fundamentally, a garbage disposal just attaches to the sink’s drain, is connected to the drain pipes, and plugs into an outlet under the sink. With a few tips revealed in this article, you can have a new disposal installed in less than an hour.
Before replacing your disposal, however, be sure you don't have one of those common problems you can easily fix without buying a new unit. (See "Fixing a Garbage Disposal.")
Buying Your Replacement Disposal
Garbage disposals are rated in horsepower (HP), typically from 1/3 to 1 horsepower or more. Don’t replace yours with a smaller one; always go with the same size or larger. Your current disposal should have the horsepower rating printed on it. If not, follow these guidelines for selecting the proper size.
1/3 HP: Light duty, for an apartment or small family.
1/2 HP: Medium duty, for a small family or home.
1.0 HP: Heavy duty, for a large family or home.
Connections for garbage disposals are largely standardized so they're all interchangeable without requiring any special fittings. If you want to be ultra safe, however, buy a replacement of the same brand.
Removing the Old Disposal
Take everything out of the cabinet under your sink, and put a few rags down, or a shallow pan to catch water when you disconnect the drainpipes.
Unplug the electrical cord from the outlet. (Roll it up and wrap it with a rubber band if you’d like to keep it out of your way.) If you have a dishwasher hose connected to your garbage disposal, loosen the clamp and remove the hose.
You’ll see a drainage tube coming out of the disposal going into another drain tube with a ring around it. Turn the ring with your hand (or with a pair of channel-lock pliers if it’s too tight) to loosen it. Loosen similar rings until you’re able to disassemble the drainpipes from the disposal’s tube. You don’t have to remove the tube connected directly to the disposal. (Pay attention to how the pipes came apart because you’ll need to reassemble them.) Mop up any water that may have escaped the pipes.
Where the disposal connects to the sink drain, you’ll see a ring that has three “ears” equally spaced around the ring. Looking at the ring from below, you’ll want to turn it counter clockwise to loosen it. It will probably be very tight and require tapping on the ears with a small hammer or other tool to get it to turn.
CAUTION: After one-third of a turn, the garbage disposal will come loose and fall. It’s quite heavy, so be prepared to catch it, or stack a pile of magazines under it so it can only drop a half inch or so. Even then, be prepared to stabilize the disposal when it comes loose. When it’s loose, you can remove the disposal from under the sink.
Installing the New Disposal
Before you begin, you need to disconnect the electrical cord from the old disposal and connect it to the new one. This requires unscrewing the cover plate on the underside, untwisting the wires, and loosening the retainer holding the cord in place. Use the reverse procedure to connect the electrical cord to the new disposal.
You’ll likely also need to connect the disposal’s drain tube, which will require a wrench or screwdriver. (Follow the instructions that came with the disposal.)
Important: If your dishwasher drain was connected to the old disposal, you'll need to knock out the plastic plug inside the tube where the dishwasher hose connects to your new unit. Refer to your instructions.
Now you can attach the disposal to the sink. If it’s too heavy for you to hold in place while you turn the attaching ring, try stacking magazines to the exact right height to rest the disposal on. Turn the attaching ring to tighten it but don’t tighten it all the way yet. First turn the disposal around as needed so the drain tube lines back up with the drainpipes in the same direction as before. Now tighten the ring, using a small hammer or other tool until it's tight.
Reassemble the drainpipes (and reattach the dishwasher hose, if applicable); then run water in both sides of the sink (and run the dishwasher, if necessary) to test for leaks. Retighten connections as needed.
Plug the electrical cord back into the outlet, and test the disposal. It should work perfectly!
