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How To Install A Garbage Disposal Safely Hero Image

How To Install a Garbage Disposal Safely

On your to-do list: learning how to install a garbage disposal. Even better? Learning how to install it safely. These food-removing machines are common in North America—over half of all homes have one beneath their kitchen sink. While these appliances can seem frightening, the installation process doesn't have to be. Here, Abt's experts break down the process and help users learn how to install a garbage disposal safely.

Why Use One in the First Place?

If this is your first time using a garbage disposal, know that the benefits are many. From easy food disposal to simple after-dinner cleanup, leftover waste can be removed in just an instant. Other pros can be found all around the house: food that would rot in outdoor trash cans (and attract outdoor creatures) is removed, and it's an easy way to use fewer garbage bags in total. If you're looking to lessen your trash output, this is one simple and easy way to do so. Not all foods can go down the kitchen sink and into the garbage disposal, though: we'll get to that later. First, we'll dive into the process of how to install a garbage disposal safely—and how to remove one that's no longer working.

Removal and Installation from Start to Finish

There are a few tools you'll need to have before you get started, so make sure you have these on hand before you clear out your under-counter cabinets and get ready to work. You'll need:
  • New Garbage Disposal
  • New P-Trap Complete with J-Bend
  • Flathead and Philip's Head Screwdriver(s)
  • Hammer
  • Allen Wrench/Hex Key
  • Channellock 900 Size Pliers
  • Non-Contact Voltage Tester
  • Bucket for Beneath the P-Trap
  • Plumber's Putty
  • Plastic Putty Knife and Wood Scraper
  • Electrical Wire Tester

Removing Your Old Model

If your kitchen sink already has a disposal installed, you'll need to remove it before going any further. Completely empty your cabinet under your sink and place a plastic tub or bucket under the pipes to catch any water. Take a look at your existing model—it'll be attached to the bottom of your drain and connected to your p-trap. If you don't have an existing one installed, these are steps you can skip.
Above, see snap spring and screws flange assembly. A plastic nut flange assembly will not have the screws.
  1. Before you do anything, turn off the circuit breaker for the kitchen and unplug the power cord. If hardwired, remove the access cover at the bottom (with power off). Disconnect wire nuts and locking ring from green field or rolmex. Use the electrical tester to verify the power is disconnected. These are important steps to ensure that your garbage disposal is installed safely.
  2. Remove the existing P-trap only first: use your channel lock pliers to grip the fitting and twist to the left until it releases. Place your bucket underneath as you detach to catch any stray water or drippings.
  3. Disconnect the dishwasher hose if applicable. It may be connected to a separate dish wye fitting. If applicable, use your flathead screwdriver to remove the screws that hold this hose in place, and let the hose rest in the bucket to drain.
  4. How to (un)install a garbage disposal safely: it's time to remove your old one. These are heavy, and you don't want them falling. Place one hand just beneath the old disposal, and use the other hand to twist it off the bracket to release. That way, you'll be ready to catch it right as it falls from the flange.
  5. The mounting bracket will be the next piece to uninstall. There are two kinds: one secured with a plastic nut, and the other will use a spring clamp to release. Insert your hex key into the circular loops on the bracket and pull to the left until it spins down the side ramp. Abt's specialist installers say that it will likely stick during this process, so be ready to pull to the left hard.
  6. Everything is removed apart from the power connection: either unplug the appliance cord or follow your home lines into the bottom of your old model and remove the cover plate that hides these connections. Disconnect the electric connection by removing wire nuts from hot and neutral and take the ground off the green screw.
  7. Finally, we're going to remove the flange. Unscrew and remove. Clear away any old plumber's putty that was holding the system in place with a wood shim for best results: you're unlikely to scratch your sink's surface that way. Alternatively, use a plastic putty knife.

How To Install a Garbage Disposal Safely

Once you've done all the work of unloading your old garbage disposal, it's time to charge ahead and attach the new one. It's going to be fairly similar but easier—you're already familiar with all of the parts and you have all of the tools, so reinstalling won't be difficult. You're almost doing the same process in reverse.
  1. No matter what brand or model you have, take a look at your device's instructions and follow them if they divert from ours. But your first step should be heading to your circuit breaker and turning the power off before moving forward. Double-check with your electrical tester that the power is disconnected.
  2. The first step is to install the flange at the top of the sink opening. Apply a half inch roll of plumbers putty to the bottom of the flange ring and press into the sink opening. Use one hand to press down the flange and the other to attach a paper ring underneath the sink then either install the plastic nut or assembly and snap ring.
  3. If you're installing with a plastic nut, do not overtighten it yet. If you're using a snap ring connection like those found in GE, tighten the screws after the snap ring is installed. These will be tightened all the way. Brands that include this construction are Franke, Frigidaire and Whirlpool.
  4. If your dishwasher is draining into the disposal, you will need to knock out the plug on the disposal. Before hanging it, use a hammer and standard screwdriver to tap the plug into the disposal, then turn the disposal upside down to shake it out. If you have no dishwasher or one that connects to a separate drain, do not remove the plug.
  5. The black PVC pipe provided by the manufacturer should be installed with a spring clamp or screws and a washer facing downward. This pipe can be trimmed if your new disposal sits lower than the old model.
  6. Keep the disposal upside down to access the electrical cover plate. If it comes with a cord, you will need to install an outlet. Once the plate is removed you can wire the nut neutrals together, connect hots wires together and connect ground to green screws.
  7. The second to last step in installing your garbage disposal safely. Lift the unit up to the mounting flange and twist the locking ring into place. Lock in by hand as far as you can and use a hex key or channel lock pliers to finish.
  8. To finish connecting the drain pipe: If PVC plastic, make sure you are using a plastic nut and washer. If your pipes are metal, make sure you're using a metal nut and rubber washer. If you're going from PVC to metal, use a metal nut and rubber washer on transition from PVC to metal.
  9. Finally, install the new P-trap in the correct direction for completely sealed plumbing with the higher side leading into the disposal and the lower side leading away. If your new unit is bigger or smaller than the old one, you may need to make some adjustments to your pipe length: it's best to use a hacksaw for PVC. If installing a GE type with a plastic locking ring, do a final tightening at the bottom because it may move during pipe installation.
  10. When learning how to install a garbage disposal safely, cleanup is key. Use a wood shim or plastic putty knife to remove any extra putty. Keeping the bucket beneath the P-trap, try running the water and see if everything is watertight. To test for leaks, turn on the faucet and fill the sink three-quarters of the way, then drain to pressurize pipes.
P-Trap Arranged correctly and incorrectly for garbage disposal installation
Above, Complete P-Trap ready to re-install after installing your garbage disposal.

The Finishing Touches

While installation can seem daunting, it's well worth the effort. Some modern models contain anti-jamming technology, and there's a wide variety available on the market, from batch feed versions to continuos feed variations. If you're looking for expert help when it comes to choosing your new model or even installing it, come to the experts at Abt. Give us a call at 800-860-3577 or head into the store for local installation. We'll deliver throughout the continental United States, too—for help choosing the right one for you, check out our garbage disposal buying guide or call us at 847-954-4140.

Q&A Summary

Check out some of the most common questions everyone asks, whether they're just learning how to install a garbage disposal for the first time or have done it before and are looking to brush up on their knowledge.

What Can Go in a Garbage Disposal?

That depends on the power of your device, to a point. Most devices can handle foods like ice, cooked meats, fruit and vegetable scraps, fruit pits, corn cobs and even small bones. Things that should never go down that drain include grease and oil, non-food items, shells from clams or oysters, pastas, rice, and other starchy foods. That's because they can because a blockage. Other ones you should keep away from the drain include corn husks and coffee grounds.

How Do You Install A Garbage Disposal In A Double Sink?

Follow the instructions above, and make sure you only add food waste to the sink with the device installed. You'll likely install the dishwasher hose to the other sink's drain, too. In this case, make sure you don't remove the knock-out plug when installing. Otherwise, you'll find that water falls out this hole instead of going down the drain.

Are Garbage Disposals Worth It?

Back to our original point, the answer is likely a solid yes. Whether you live alone or cook for a massive family, you're likely to have occasional leftovers. Instead of sending them to the landfill or attracting neighborhood creatures, grind them up in your drain. They're a fast, easy and convenient way to remove food waste. Contact us for more details and with any questions at 847-954-4140.