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Hot Or Cold Water With A Garbage Disposal? And Why

When running a garbage disposal, it’s recommended to use cold water. Cold water helps solidify any grease or oil that may be in the food waste, making it easier for the disposal to grind it up and prevent clogs in the plumbing system.

Hot water, on the other hand, can liquefy any grease or oil and cause it to coat the pipes, potentially leading to clogs in the long run. Additionally, running cold water can help to keep the garbage disposal cool and prevent overheating.

It’s a good idea to run the cold water for at least 15 seconds before and after using the garbage disposal to ensure the waste is properly flushed out of the pipes.

What happens when you run water at high temperatures into the garbage disposal?

The food wastes we put into the garbage disposals often contain some fats and oils. Normally, these fats and oils are ground and disposed of through the drain pipes along with the food wastes. However, if you add hot or boiling water into the disposal, the fat contents will melt and separate from the food wastes. Once these fats reach the drain pipes, they will solidify again and stick to the pipe’s walls. Gradually, this fat build-up will lead to clogs.

For this reason, it is important to run cold water into the disposal and not hot water. Cold water will not melt fats, so the fat content will safely move down the drain without creating clogs.

When to use boiling water?

Even though hot water shouldn’t be used when running your garbage disposal, there is one time when you can pour boiling water. That is while cleaning your garbage disposal.

When you use your garbage disposal regularly, some of the fat contents in the food scraps will stay stuck in it. This will affect the efficiency of the garbage disposal, and hence the disposal should be cleaned regularly. Pouring hot water into your garbage disposal is a great method to get rid of these fat contents. The hot water will melt the fats stuck inside the disposal and wash them away through the drains.

But won’t these fats then clog the drains? That is very unlikely. The accumulation of fat contents in the drain pipes happens only if you use hot water every time you run the disposal. Using boiling water once a week won’t cause any issues with clogging.

So, when in doubt, always use cold water when running your garbage disposal. Hot water should only be used when cleaning the disposal.

It is important to remember that you should not run the garbage disposal when there are chances of overflowing wastes in it. This can cause many problems like clogging, etc.

How much water do you need to run?

There is a common misconception that garbage disposals use lots of water. But that is very untrue. A typical garbage disposal uses only 1.32 gallons of water per day. That is how much you flush down a toilet each time. Unbelievable, isn’t it?

Therefore, you don’t need to run water at full blast when using the garbage disposal. Open your kitchen faucet just a little so there is a constant stream of water, no more.


Can I run garbage disposal without water?

You should not run your garbage disposal without water. If you run it without water, the garbage disposal will get stuck and this can lead to damages.

You should use run a continuous stream of water when using the garbage disposal because water will wash away all the ground food wastes in the garbage disposal. Without water, the ground wastes will stay inside the disposal causing it to jam. In addition, the water also provides lubrication during the grinding process to easily cut down food wastes. Lack of water, or not running it at all will damage the grinding components and the motor of the garbage disposal. Therefore, it is important to make sure you run enough water to keep the disposal running.

How long should you run water?

You should run water as long as the garbage disposal is running and then some more. The best practice is to start the water first, and then turn on the disposal. Once the garbage disposal is turned off after grinding, keep running the water for a little while more. Doing this will wash away any food particles left in the grinding chamber of the disposal, and this helps to keep the garbage disposal clean.

My name is Thomas Anderson, author of DisposalQA. I have 15 years experience working as a plumber in CA, and this is where I answer common questions about garbage disposals.