Garbage Disposal Backing Up Into Sink

It can be extremely frustrating (not to mention gross) when your garbage disposal starts to back up into the sink.

What causes this issue, and how can you fix it?

Blockages, overuse, and incorrect installation can cause your garbage disposal to back up into the sink. Manually removing blockages, plunging the sink, and cleaning the drain with a mixture of vinegar and baking soda will fix the problem in most cases. Try to avoid chemical cleaners, as they can damage your plumbing, and call a plumber if the problem persists.

In this article, we’ll discuss the three main causes of garbage disposals backing up into the sink. Next, we’ll offer a step-by-step procedure to fix the problem.

We’ll also talk about whether it’s recommended to use chemical cleaners like Drano to eliminate blockages in your disposal.

What Causes The Garbage Disposal To Back Up?

There are three main reasons that your garbage disposal might back up into your sink. These include blockages, overuse, and incorrect installation.


The most likely reason behind your garbage disposal backing up is a blockage. As food and other types of debris build up over time, they can cause an obstruction inside the disposal.

Often, when you’re dealing with a blockage, you’ll notice that your sink starts to drain much more slowly than it usually does. If you choose to ignore this, the blockage will get worse, and that’s typically when your garbage disposal begins to back up.

Foods That Cause Blockages

Many people don’t realize that garbage disposals are not meant to dispose of any kind of food waste. For example, items like celery stalks, eggshells, coffee grounds, potato peels, banana peels, and corn husks can build up and create blockages

Grease and oil are two other items to avoid putting in your garbage disposal.

Although your disposal is capable of grinding most types of food waste, the items mentioned above react with water and form a coating that eventually clogs the disposal completely.

Over time, food waste can coat the drain trap, which is a U-shaped plumbing fitting situated past the disposal discharge pipe.

Lack Of Water Leading To Blockages

Even if you’re only using your disposal to get rid of light food waste, it can still cause a clog. This most often happens if you don’t flush your disposal with plenty of water while it’s grinding. 

It’s necessary to put quite a bit of water down the disposal during use so that the waste is efficiently flushed through the pipes.

The most effective way to prevent blockages in your disposal is to flush it with lots of water as it runs and for several more seconds after turning it off.


Overuse can also cause your garbage disposal to back up. If you’re putting more waste into your disposal than it can handle, it may begin to come back up into your sink.

The simple solution here is to reduce the amount of waste you put into the disposal. Ensure the disposal has finished processing any items put into it before adding more.

Of course, avoid disposing of coffee grounds, eggshells, and various peels in your garbage disposal as they can cause blockages and lead to the disposal backing up.

Incorrect Installation

If you often notice water backing up into the side of the sink without the disposal, you may be dealing with an installation issue. 

It’s possible you have a T-shaped connection located between the tailpiece of the sink and the disposal. This can keep water from flowing downward.

When incorrect installation is the root of the issue, fixing the problem is often as simple as replacing the T-shaped connection with a Y-shaped one.

What Do You Do When Your Garbage Disposal Backs Up Into The Sink?

If your garbage disposal has started to back up into the sink, you may not have to call a plumber just yet. There’s a simple series of steps you can take that will usually solve the problem in less than an hour.

Step 1: Look For Blockages

Start by turning off the power to your garbage disposal. Turn the switch off, unplug it, and if you want to go the extra mile, turn off the circuit breaker as well.

Next, use a flashlight to look inside the disposal and see if there are any blockages. If you find any, use a long tool like pliers, tongs, or a disposal wrench to remove it.

Step 2: Use A Plunger

If your disposal is extremely backed up, manually removing clogs may not be enough. Instead, get a sink plunger, which has a flat cup.

Turn on the faucet until there are a few inches of standing water in the sink, and then plunge the drain for a minute or two.

Step 3: Utilize Drain Cleaner

Mix together a homemade drain cleaner by combining equal parts vinegar and baking soda. Pour this cleaner down the drain and wait for a half-hour.

Next, run hot water down the drain for at least a minute to thoroughly flush out the disposal.

Step 4: Test Your Disposal

Now that you’ve taken steps to remove any blockages, it’s time to see if your disposal is working properly again. Test it with some light food waste. Restore power to the disposal and see if it runs, or if it’s still backing up into the sink.

If your garbage disposal is still backing up, we recommend calling a plumber to resolve the issue. Sometimes, the problem has to do with incorrect installation, which a professional will be able to fix.

Will Drano Unclog A Garbage Disposal?

Photo: Mike Mozart / Flickr / CC BY 2.0

According to the Drano website, its Max Gel Clog Remover and Dual-Force Foamer Clog Remover are recommended for clogged garbage disposals. Although Drano can undoubtedly be effective, it’s not the safest option.

All Drano products use sodium hydroxide (also known as lye or caustic soda) as their main ingredient. The problem with this is that it can damage your pipes and cause severe burns.

When sodium hydroxide combines with water, it releases heat. If it lingers in the drain or disposal and mixes with ammonia or bleach, it can also release harmful fumes. 

For safety reasons, it’s generally recommended to use a mixture of vinegar and baking soda or boiling water and salt to make a safer drain cleaner. 

Not only are they much less hazardous, but these DIY cleaners contain ingredients that you typically already have around the house and won’t have to run to the store for.


If your garbage disposal is backing up into the sink, then you may be dealing with overuse, blockages, or incorrect installation.

Try removing the blockages, plunging the sink, and using a mixture of baking soda and vinegar to flush out the drain and disposal. In most cases, this will resolve the issue.

We recommend avoiding chemical cleaners since they can be hazardous and damage your plumbing.

Be sure to call a plumber to take care of the problem if your disposal continues to back up into the sink after taking these steps.

Jessica Allen

Jessica is a freelance writer and editor who has years of experience writing about home improvement and interior design. When she’s not typing away in her office, you can find her doing yoga in her backyard or curling up with a good book.

Recent Posts