How to Replace a Garbage Disposal

One minute, you’re seamlessly garbage disposal is making that low, humming indicating the motor is caput. Or maybe you’re just dealing with a leaking garbage disposal.  Either way, it’s time for a replacement, right?


Fear not! If you have some basic home DIY skills, you can easily learn how to install a garbage disposal unit without incurring the cost of a professional plumber.


Installing a garbage disposal in a single drain sink takes around 20-30 minutes and a few household tools. Let’s get started.


1. Understand What You Need and Gather Materials

The best plan of action as you replace your broken garbage disposal is to start by understanding your current unit.



You see, there is quite a bit of variation between garbage disposal units. For starters, there are two distinct types of garbage disposal feeds:


  • Continuous Feed Disposal: The most common, the continuous feed, requires a simple switch (such as a light switch) which turns the unit on and off when needed.


  • Batch Feed Disposal: A batch feed, the other type of disposal, has two chambers and is more commonly used in households that don’t produce much food waste and/or are prone to dropping unwanted items (such as utensils) into the disposal.


Next, you’ll want to consider horsepower. The vast majority of households don’t require more than a ½ horsepower motor. However, if you have a large family or entertain regularly, consider a stronger motor between ¾ and 1 horsepower.


Take a look at your current unit. Note the type of garbage disposal and the amount of power it has. Then, consider how you used it. If you experienced frequent clogs, or the unit didn’t last more than 1-2 years, then find a disposal with more power.


For example, when our garbage disposal bit the dust, the first thing we realized was that it was using only ⅓ horsepower. Because we have a 4-person family and frequent guests, we decided to upgrade our unit to ¾ horsepower.



After purchasing the new garbage disposal at our local home improvement store, I also gathered my tools, including:

  • Hammer
  • Flathead and Phillips screwdrivers
  • Adjustable wrench
  • Plumbers putty
  • Light source


2. Prepare Your Space

Garbage disposal units sit under the kitchen sink, within the cabinet. It’s a place where many families stores cleaning materials and other kitchen-related items such as fire extinguishers, trash bags, etc. If you foresee any of these items getting into the way of your work space, go ahead and clear them out and then cover the space with a plastic bag or old newspaper to collect dripping, dirty water.


Lighting may also be an issue, so bring over an old lamp, a flashlight, or metal utility clamp light to help brighten up your space.


Turn the breaker to the disposal OFF before beginning this project.


3. Remove the Old Unit

To remove the old disposal, ensure the breaker and ALL POWER is off. Then, disconnect both the drain tap from the tailpipe as well as the pipe that connects to the dishwasher inlet. Keep in mind; there may be some water in these pipes.



Next, it’s time to remove the entire unit from the sink mount. Use the wrench included with your new disposal and slide it into the mount lug. Then, twist the unit. Sometimes, you have to lie down under the sink and use your strength to twist and pull at the same time.



The electrical components are still connected. To disconnect them, remove the electrical plate using the Phillips screwdriver. Then, detach the wires connected by the cable connector.



Put the old garbage disposal aside.


4. Install the New Unit

When we installed our new unit, we decided to keep the sink flange in place since it fit our new disposal and didn’t leak. To ensure it didn’t move around when we installed the new fixture, someone held is down firmly during the entire installation process.



Are you connecting your disposal to a dishwasher? If so, then start installation by knocking out the dishwasher connecting using a hammer and screwdriver.



Next, it’s time to handle the wires. Remove the electric cover and then connect the black wire in the unit to the black wire from the power source using the cable connectors/wire nuts from the old unit. Then, do the same for the white wires. Finally, wrap the grounding wire to the grounding screw (ours was a greenish/rust color) and screw back on the cover plate.



Attach the main drain pipe/discharge tube to the tailpipe using an inset gasket (included with the new unit) and then secure the two together using the screw included. Next, carefully lift the disposal and twist it into the garbage disposal mounting ring under the sink.



Remember, the disposal is heavy!


Last, secure the dishwasher pipe and ensure each fitting is tight.


You may notice some extra flanges, screws, and other parts that come with the new unit that you may not necessarily use during the install. Make sure you keep these! Garbage disposal replacement parts aren’t cheap, so it could save you money and time down the road.


5. Test the Functionality

Your garbage disposal is in! Now, it’s time to test its functionality. Fill the sink with water, then keep watching under the sink at the pipes and connections for any leaks. Use plumbers putty as needed.



Turn the breaker back on and then flip the switch. Your new garbage disposal is ready for use!


Considering the garbage disposal installation cost varies between $50 and $150+, you can save a significant amount of money by doing it yourself. The key is to be thorough and careful throughout the entire install.


You’ve got this!


Images used with permission, courtesy of Tina Jepson

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