How Garbage Disposals Function

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Wiring, Installing or Replacing a Garbage Disposal

Initially, wiring, installing or replacing a garbage disposal may seem like a challenging task. However, with the appropriate tools and a little knowledge, it can be as easy as grinding up leftovers from last night’s dinner.

Garbage disposals are the underrated champions of the kitchen. If you haven’t installed one yet, you may not value them much, but once you begin to use your garbage disposal, it will be difficult to imagine how you ever managed without one. They efficiently dispose of your kitchen waste without complaints, and with a bit of planning and time, you can live the good life–the garbage disposal life.

Before installing a garbage disposal, ensure that you have an available outlet secured by a 120 volt, 20-amp circuit breaker. Note that a GFCI outlet will not suffice. After the appropriate outlet is in place, switch off the power and gather your tools, which include:

  • Bucket & Rags
  • Plumbers putty
  • Putty knife
  • Screwdrivers
  • Hammer
  • Wire strippers
  • Wire nuts & electrical tape
  • Pipe wrench

1. Clear the area under your sink so that you have enough space to work. The first step is to disconnect and remove the strainer and all waste drain lines from the sink.

2. Place a bucket under the sink and remove the wastelines. Empty all the water from the sink into the bucket.

3. Once the waste lines are removed, remove the mounting assembly. You will see a big nut that secures the strainer. Remove the nut.

4. Take out the strainer and clear away any existing plumbers putty from around the area. Ensure that the surfaces are clean.

5. Now you can open your new garbage disposal and begin installing it. First, you need the sink flange and the mounting assembly, which includes upper and lower mounting rings and mounting bolts. Open the plumbers putty and place a quarter-inch coil of putty around the drain. Next, put the sink flange in the drain and gently press it down onto the putty.

6. Find your gasket and mounting ring and then go back under the sink. Take the gasket and the mounting ring and push them up the flange. Connect the snap ring to the flange to keep the gasket and ring in place.

7. Now it’s time to tighten the mounting bolts. Locate the three mounting bolts and start tightening them. Alternate between the three bolts and ensure that they are tightened evenly. Plumbers putty will most likely emerge from under the flange, but don’t worry; wipe away the excess.

8. Now comes the wiring. Place the disposer on its side under the sink. After switching off the breaker, remove the disposal’s cover plate to access the wiring. Connect the white and black wires to the matching wires from the power supply. Ground the supply wire and replace the electrical cover plate on the unit.

If you have a dishwasher, there’s an additional step to installing your garbage disposal. Firstly, locate the close-ended tube on the side of the disposal unit near the top where the dishwasher inlet line is connected. Using a screwdriver and hammer, take out the line plug, being careful not to let it fall into the disposal. Once the plug is removed, you can proceed with mounting the disposal. Align the disposal with the mounting assembly under the sink, using the three tabs on the unit to lock it into place. It may take some patience, but you’ll know when it’s secured. The disposal will still be slightly loose, but don’t worry; you’ll fix this later. Position the discharge tube so that it aligns with the water pipes and connect the drain line to the inlet port on the side of the disposal if you have a dishwasher. You may need to cut some PVC plumbing pipes to ensure a proper connection between the “J” trap and the disposal, particularly if you have a double-bowl sink. Once all the plumbing is connected, make sure that all nuts are tightened and the disposal line is secure. Finally, test your work by turning on the water and checking for any leaks. Turn on the power and plug in the disposal, ensuring that the water is running before flipping the switch. Always run the water when using your disposal and keep your hands and fingers away from the opening to ensure your safety. Welcome to the world of garbage disposal living!


1. What is a garbage disposal?

A garbage disposal is a kitchen appliance that is installed under the sink and is used to grind food waste into small particles that can be easily flushed down the drain. It is also known as a waste disposal unit or garburator.

2. How does a garbage disposal work?

A garbage disposal works by using a motor to spin a flywheel that is mounted on a shredder plate. The food waste is then forced against the shredder plate and is cut into small particles that can easily pass through the drain.

3. What kind of food waste can a garbage disposal handle?

A garbage disposal can handle most food waste, including fruit and vegetable scraps, coffee grounds, eggshells, and small bones. However, it is important to avoid putting hard or fibrous materials, such as bones, corn husks, or celery, as they can damage the shredder.

4. Is it safe to put your hand into a garbage disposal?

No, it is not safe to put your hand into a garbage disposal. Even if the unit is turned off, there may still be sharp blades that can cause injury. It is recommended to use tongs or pliers to remove any objects that may be stuck in the disposal.

5. How do you clean a garbage disposal?

To clean a garbage disposal, turn off the power and use a soft brush or cloth to clean the inside of the unit. You can also use a mixture of baking soda and vinegar to remove any odors. It is important to avoid using harsh chemicals or abrasive materials that can damage the unit.

6. How long do garbage disposals last?

A garbage disposal can last between 8 to 15 years, depending on the frequency of use and how well it is maintained. It is important to follow the manufacturer’s instructions for use and maintenance to prolong the life of the unit.

7. Can a garbage disposal be repaired?

Yes, a garbage disposal can be repaired if it is not working properly. Common problems include jamming, leaks, or a motor that is not turning on. It is best to hire a professional plumber or appliance repair technician to diagnose and fix the problem.

8. Is it difficult to install a garbage disposal?

Installing a garbage disposal can be a difficult and time-consuming task. It involves connecting the unit to the sink and the electrical supply, and may require some plumbing skills. It is recommended to hire a professional plumber to install the unit.

9. Can a garbage disposal be used with a septic system?

Yes, a garbage disposal can be used with a septic system, but it is important to choose a unit that is specifically designed for septic systems. These units have special features that help break down food waste and prevent clogs in the septic system.

10. How much does a garbage disposal cost?

The cost of a garbage disposal varies depending on the brand, model, and features. A basic unit can cost between $50 to $100, while a more advanced unit can cost up to $500 or more.

11. Are there any safety tips for using a garbage disposal?

Yes, there are several safety tips for using a garbage disposal. These include avoiding putting your hand into the unit, never putting non-food items into the disposal, and running cold water while using the unit to help flush the waste down the drain.

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