Replacing a garbage disposal can seem like a daunting task, but with the right knowledge, tools, and supplies, you may be able to do it on your own. In this article, we’ll teach you how to replace your garbage disposal.

Gather Tools and Supplies to Replace Your Garbage Disposal

This project doesn’t require too many crazy supplies. Here’s what you need.

  • Flathead and Phillips screwdrivers
  • Plumber putty or silicone sealant
  • Plastic wire nuts
  • Garbage disposal unit
  • Sink flange
  • Mounting kit
  • Optional supplies
    • Hacksaw
    • Regular and needle nose pliers

How to Remove a Garbage Disposal

Learning how to replace a garbage disposal can be pretty easy. But, make sure you really need a new system before jumping in. If you just have a jammed disposal, you can look or feel around in the drain for a blockage. Sometimes pulling out a lodged item will fix your disposal fast. But, your disposal unit may be cracked, leaking, painfully loud, or completely dead. In that case, a new unit is your best bet.

  1. Turn Off Power
    1. Before you take out the old unit, you’ll want to turn off the power to the garbage disposal. Disposal units are an electrical appliance. So, if you keep the power on while removing or installing the disposer, you could get shocked. Plus, it might give you greater peace of mind, especially if you’re concerned about keeping your fingers intact.
    2. Go to your home’s breaker and turn off the switch sourcing the power to your garbage disposal. Try turning on the disposal to make sure that you flipped the right switch. Some disposals might be plugged into an outlet under the sink. In that case, just unplug it.
  2. Get to Know Your Disposal Unit
    1. When you look under your sink, you’ll mostly see pipes. The garbage disposal unit is the large object connected directly to the bottom of the sink, and it doesn’t look like a pipe. Most kitchens have a double sink. Beneath, there is a pipe connected to the bottom of one sink and the garbage disposal connected to the other. A discharge tube usually connects the garbage disposal to the pipe coming from the other sink.
    2. Pay attention to the make and model of the current garbage disposal. This will help you when buying the new unit.
  3. Disconnect the Discharge Tube
    1. The pipe coming out of the side of the unit is a discharge tube. Unscrew the tube’s connection. Then, tug it free.
    2. If your disposer is older, it might be connected to the dishwasher with another tube. Disconnect that the same way.
  4. Disconnect the Unit from the Mounting Ring
    1. The mounting ring is directly connected to the sink. As soon as you disconnect the mounting ring from the unit, the large, heavy unit will drop to the ground. It’s smart to stack some items beneath the unit to keep it from causing damage when it falls. Once you’ve created a stack beneath the unit, twist the metal ring until you feel it release.  
  5. Disconnect the Power Supply
    1. Turning the unit over, you’ll see a plate covering. Remove this and you’ll see the electrical wires. Remove the copper grounding wire from its place around the green screw. Remove the plastic wire nuts to disconnect the power supply.

How to Replace the Mounting Unit on Your Garbage Disposal

If there aren’t any leaks in your current mounting unit, then you can leave it as it is. If your new disposal unit won’t fit with the mounting unit or if your mounting unit is leaking, put in a new one.

  1. Remove Mounting Unit
    1. Take off the rubber ring and the bottom of the mounting assembly. Next, you can use a screwdriver to loosen the nut. The nut has lugs coming off it that the screwdriver can fit into. The screwdriver will add leverage and help loosen this. The mounting ring should come off easily after that.
  2. Remove Sink Flange
    1. Now come out from under the sink and take out the sink flange. The flange is the metal piece around the drain opening. You might need to go back under the sink and push on the bottom of the flange to loosen it. You might need to use a putty knife to remove old putty from beneath the flange.
  3. Install New Sink Flange
    1. Pat the sink drain dry. Put new plumber putty or silicone sealant on the bottom edge of the flange. This will act as an adhesive connecting the flange to the sink drain. Push the bottom of the flange through drain and press the flange’s edge to the sink. Press down on the flange for a few moments to help the putty set.
    2. It will take 10-20 minutes for the putty to fully set. It’s best to weigh down the flange for that time. Place something heavy inside the sink, on top of the flange. The old disposal unit can act as a weight.  
  4. Add the Mounting to the Flange
    1. Place a rubber gasket around the sink flange. (We’re back under the sink now.) Then, add a second flange. Follow that with the mounting ring. You’ll need to hold all of the mounting assembly pieces while placing and tightening screws through the mounting ring and backup flange. You want each screw to be equally tight.

How to Install New Disposal Unit

If you just took out your old unit, this should be easy. For the actual garbage disposal replacement, just follow the same steps, but in reverse.

  1. Connect to Power Source
    1. Make sure that the power is turned off still.
    2. You’ll see wires of different colors when you open up the plate on the bottom of the unit. Place the white wires together and secure them with plastic wire nuts. Any other wires of the same color should be placed together and attached with wire nuts.
    3. Then, place the copper grounding wire around the green screw. Cover the electrical area with the plate again.
  2. Connect the Discharge Tube
    1. Slip the tube into the opening on the side of the disposal unit. Then, secure it by tightening nuts or screws around the tube to the unit.
    2. If the discharge tube is too long for the new disposer, you can fix that easily. Measure the tube to decide how long it should be. Then, use a hacksaw to cut the tube to the length you want.
    3. If the tube is too short, you’ll have to buy a new one.
  3. Connect New Disposer with the Mounting Unit
    1. Lift the unit and insert it into the mounting ring. Hook a screwdriver through the mounting tabs and turn the unit until it is secure.
  4. Check for Leaks
    1. Turn on the sink and let the water run for about 30 seconds. As the water is running, feel around the connecting points of the unit for any leaks.
    2. If there are leaks, turn off the water and thoroughly dry the area. Then, you can use thread seal tape or Teflon pipe joint compound on the leaky area.
  5. Check for Disposal Function
    1. Now add power to your disposal by turning the power on at your breaker. Hit the switch to the disposal and see if it’s working.
    2. If the sound of your disposal seems horribly wrong, you may need to reach out to a professional plumber.

Learning how to replace garbage disposal can mean a quieter, nicer-smelling, more-efficient kitchen. Plus, it’s a project that you can tackle on your own. So, break out your tools and get started.

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