How to Install a Garbage Disposal?

How to Install a Garbage Disposal

Has your old garbage disposal given up the ghost? It is time to replace with a new one. After you buy the best garbage disposal that is right for you, the next step is to install it. What to do if you don’t want to pay a hefty installation fee? Your best solution is to install it yourself. Even if you have no experience whatsoever installing appliances in your home, all you need is a little thoughtful preparation, the right tools and materials, and a little perseverance to install your new garbage disposal yourself. Self-installation is much more cost-effective than having a professional do the work, and DIY installation helps you develop your hands-on skill set. Below is our step-by-step guide to DIY garbage disposal installation.


Before You Begin: Some General Notes on Installation

– If you are installing a garbage disposal in a sink that has never had one, you may need to get an electrician to wire an outlet and switch before installing. It may cost you more money, but it will definitely be a lot safer than attempting to wire it yourself.

– Make sure that you remember to disconnect and reconnect the dishwasher drain hose before and after installation. Additionally, make sure the dishwasher drain port on the new disposal is “punched out” like it says in the instructions.

– It is a very good idea to remove the existing mount and sink drain flange and replace them with the new parts from your new disposal.

Alternatively, you can easily find a local service provider near you for garbage disposal installation.


Materials and Tools You Will Need:

Required ToolsA bucket, a standard claw hammer, a pair of adjustable pliers, a screwdriver (Phillips Head or Flat Head), a plastic or metal putty knife.

Required MaterialsNew Garbage Disposal, a small container of plumber’s putty.

Optional Tools That May Come In HandyNeedle nose pliers (for wiring), a rubber mallet, a ratcheting screw bit driver (easier to use than a standard screwdriver).


Step-by-Step Directions for Garbage Installation

1. Cut the power to the outlet under your sink at the breaker box. If you already have a switch that controls that outlet, verify the power to the disposer is off by flipping the switch on and then off. Put the bucket underneath your P-trap pipe to make cleanup after installation easier. Lastly, disconnect the disposal from the drain pipe.

2. Use your pliers to pop out the existing strainer/baffle and the existing flange. You will need to make sure you scrape off any old plumber’s putty and debris so that the sink drain is clean and ready for the mounting hardware from the new garbage disposal.

3. Take a grape-sized lump of plumbers putty and roll it like you are making a clay snake. The resulting ring of putty should be no wider than a No. 2 pencil and the same width all the way around. Press it down firmly around the top of sink flange opening.

4. Carefully disassemble the flange and mounting bracket that came with your new garbage disposal. Pay attention to how you take it apart so you can put it back together.

5. Press the flanged down firmly on top of the loop of plumbers putty. The putty will squeeze out of the edges. Leave it be for now.

6. Install the lower mounting assembly from underneath the sink. Begin by loosening the screws enough to give you adequate wiggle room to get all the pieces together. Place the parts in this order:

  • Fiber gasket the cardboard-looking ring) on top closest to the underside of the sink flange
  • Upper mounting ring
  • Lower mounting ring

Press all of these pieces up against the bottom of the sink flange and then pop the snap ring into its groove to hold the assembly together. You may find it helpful to have another person pushing down on the sink flange from above while you maneuver the rest of the parts into place underneath and get the snap ring into place.

7. Take a long screwdriver and a hammer (I prefer a rubber mallet), and use them to punch out the dishwasher drain plug in the side of the new disposal. Make sure you remove the plug itself and any pieces of the plug before completing installation.

8. Move the disposal into place and hang it from the mounting bracket by lining up the mounting tabs. Use the wrench included in the box and a screwdriver to lock it securely into place. I have found that this is often the most difficult part of installation, so you may want an extra pair of hands to help.

9. Push the discharge tailpipe into the bottom of disposal and clamp it. Rotate your disposal so that it lines up with the discharge pipe and your drain trap. Once you have everything in place, tighten everything up. Lastly, push the dishwasher drain hose over the side inlet of the disposal and clamp it.

10. Clean up an excess putty around the flange with the putty knife. You will notice that depending on how much you used that it may continue to squeeze out over the next day or two. Clean it up with the putty knife if it continues to appear.

11. Test your installation by plugging up the sink with the included stopper and then filling the sink with water. Check under the sink to see if there are any leaks or drips.

12. Once you have established that everything is watertight, connect the new disposal to power.

13. Flip the breaker back on and then test your new disposer.

Related: How to Install a Garbage Disposal Air Switch


Final Notes

Insinkerator and Waste King both have online video tutorials for installing their garbage disposals should you need help or if you want to see the installation done before attempting it yourself. If you can follow directions carefully and troubleshoot any issues on your own, you may be saving yourself anywhere from $150-$200 for a professional installation. In the end, remember that this is an easy installation and that you can do it, just be safe, work slowly, and always look at directions before beginning work. Good luck!

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