Informational Guide

How Does A Garbage Disposal Work?

Learn everything you have been wondering about garbage disposals in this comprehensive info guide.

by Ian Haynes

Garbage disposal systems make our lives simpler, our meal clean-up manageable, and our kitchens cleaner. Almost every modern home depends on one, and once you’ve used one, you can’t do without them. But have you ever wondered: how does a garbage disposal work?

If you have, you may also need answers to related queries such as: How long does it take to replace a garbage disposal? How long does it take to install a garbage disposal? Knowing the workings of a garbage disposal system arms you to diagnose problems and rectify them if any arise.

And if you don’t have one installed, learning how one works will prepare you to DIY the installation!

Splash Guard

The splash guard is a rubber gasket placed between the sink drain and the garbage disposal canister. It prevents larger food particles from slipping in and keeps any food debris from regurgitating out when the motor is in action.

Hopper Chamber

The hopper chamber is a hollow cylinder that houses the disposal. It consists of two portions: the upper and lower chambers.

As food enters the disposal system, it collects in the upper chamber, from where it moves to the motor, which is situated in the lower chamber.

As the motor grinds the food, it moves down into the drainpipe, where it is disposed of.

Flywheel And Shredder Ring

The flywheel consists of a rotating turntable connected to the shredder ring, and it serves to accumulate any food that hasn’t yet been minced enough to pass through the shredder ring.

The inside of the shredder ring has small, sharp grooves that grind and fragment the food pieces on the flywheel.

Waste Line Connector

The waste line is situated in the lower hopper chamber. Crushed food falls through the shredder ring into the waste line and is then flushed out into the drain pipe.

The drain pipe then disposes of the waste into the sewer.


The impeller houses the blades that grind food. It works in tandem with the flywheel and the shredder ring.

The spinning impellers force the food onto the shredding ring to break it down.


Two wiring arrangements are commonly used for garbage disposal systems. In the first instance, the unit is hardwired directly to a specific power circuit. Otherwise, it can be wired with an appliance cord connected to a wall outlet.

So how much power does a garbage disposal use? To put it simply, it roughly uses the same amount of energy as an iron. Expect the disposal unit to consume anywhere between 500 to 1500 watts if used for a short time.

garbage disposal parts

How A Garbage Disposal Works

Many people perceive garbage disposal systems to function like blenders, where the food enters and is chopped into tiny pieces by a rotating motor.

However, the mechanism at work is slightly different. The spinning impellers use centrifugal force to push food against an immobile grinding ring to break it.

This shredding process leaves large and small waste particles in a pulp.

Next, running water flushes the food through the grinding ring and into the waste disposal drain. From there, it flows into the sewer.

To prevent the disposal unit from clogging up, avoid breaking down any grease, fat, or oil-rich food particles. Instead, dispose of greasy waste in a physical bin.

Also, avoid putting any fruit or vegetable peels directly into the disposal unit. Good dishwashing soap can help break up the gunk and clear out any collected grime.

However, If using the garbage disposal is the only option, feed them slowly into the grinder, one piece at a time.

Remember, running water through the unit will help to flush away semi-large waste particles that may be stuck.

Be sure to use plenty of water as it helps to keep your garbage disposal clean and unclogged. And if you’re still unclear about how it works, watch this video for a better explanation!

Garbage Disposal Installation And Removal

Typically, the installation cost ranges between $120 to $600, with the unit itself costing anywhere between $100 to $250 and above.

If you need to replace your unit, browse through your local appliance retailer and consider your budget. Repairing costs, inclusive of labor charges, will cost you somewhere around $250.

However, the good thing is that repairing or installing a garbage disposal unit isn’t a time-consuming endeavor. You can have it up and running in less than 4 hours!

Often, the costs of repairing a unit are higher than replacing it. It’s always better to swap older, rundown systems for newer ones, especially if you’ve had yours for years.

If you want to save on the cost of hiring a plumber, you can attempt to replace it by yourself.

This way, you only have to pay the cost of the unit or the parts. It can save you up to around $75.

At this point, you may want to know: how long does a garbage disposal last?

Though garbage disposal units are sturdy and generally last up to 10 years, it’s essential to get it fixed right away if yours stops working. Ignoring the problem can lead to further clogging of your sink.

People Also Ask (FAQs)

How many amps does a garbage disposal use?

A garbage disposal unit can use anywhere between 15 to 20 amperes.

How does an air switch work for a garbage disposal?

An air switch allows you to disconnect the appliance from the electrical grid and connect it to an approved outlet. Another line runs to the side of your sink. You can mount the button here or on the countertop.

How long does a garbage disposal usually last?

Most garbage disposal units have a life of around ten years, after which they begin to clog.

What kind of waste should not be put in a garbage disposal?

Avoid putting animal bones, pits and seeds, celery, rice, pasta, coffee grounds, and all other greasy products in your garbage disposal. For more information, check out our piece on what not to put in a garbage disposal.

How much does Lowes charge to install a garbage disposal?

Lowes will charge you around $100 to install a garbage disposal.


A garbage disposal unit is the unsung hero of every house across the States; maintain yours to avoid unnecessary stress!

Installation can cost you $80 if you prefer to go the DIY route. If you choose to have it installed, the cost can go higher. Once fitted, expect it to last you up to a decade.

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.