Can you put a sponge in the dishwasher?

A sponge isn’t exactly the cleanest item in the kitchen as many studies have been quick to point out.

In fact, it could be the filthiest – when used to clean crockery but dumped in the bottom of the sink where it swims in a puddle that guarantees it stays wet until the next cleaning session.

That practice, as opposed to wringing and making sure it properly dries out on a dish rack, harbors the most bacteria population for any given area which could be detrimental for whoever is eating on a plate that has been washed using the sponge.

But that isn’t to say that the latter method doesn’t harbor bacteria growth too, and cannot be a source for concern.

It does harbor, and definitely could at alarming quantities on the long run, even with proper cleaning practices.

That’s why a research published in 2017 and also a publication issued out by the Cooks Illustrated magazine, advises against the use of sponges for longer than two weeks, even when cleaned, wringed and dried out between cleaning.

They advise that you purchase an entire pack of sponge, ensure that you clean and dry any used sponge as often as every other day (or every single day if possible), and be on a constant loop of sponge replacement every week or two weeks until you run out of the pack. Then purchase a new one!

That’s what the research in 2017 describes as “the cheapest way to stay hygienic”, and to be honest, it isn’t wrong at all.

Now speaking of sponge cleaning, of course there are numerous ways you can go about it, but could you actually do it inside a dishwasher?

Of course, and that’s one of the three main methods advocated by many Health Authorities around the world as the healthiest practice. Here’s the quick answer on how to properly do it.

Clean sponges in the dishwasher by placing them in the top rack of the appliance and using the longest, hottest cycle setting. This will get rid of 99.9998 percent of bacteria thriving inside the cervices of the sponge. Alternatively, a normal heat-dry cycle of a dishwasher is sufficient to achieve such cleaning result too.

How to clean a sponge in the dishwasher


Remove food residue from the sponge first and then run under water to eliminate most of the soap in it. Without this, the dishwasher could build up suds which could affect the quality of washing.

Place it in the top rack

This has the optimal temperature that wouldn’t destroy the fibers of the sponge. In case you’re wondering, the bottom rack receives the hottest water as opposed to the top rack.

A long hot cycle is better

This exposes the sponge to hot water for long which destroys most of the thriving bacteria. Alternatively, the regular cycle with drying should also produce a pretty decent cleaning result.

Keep in a dry place

After cleaning in the dishwasher, place the sponge in a sponge tray or dish rack to remove any moisture the dishwasher has failed to remove. This keeps the sponge dry and therefore makes it an unattractive place for bacteria to flourish.

Clean sponges regularly

As far as cleaning a sponge is concerned, it’s best to do it whenever you run the dishwasher. That’s as often as every day! It will keep the sponge clean between uses which will minimize the risks of food poisoning. Make to avoid placing clean sponges in wet areas and avoid using sponges to clean surfaces used to handle meat. Use a disposable paper for these surfaces.

What other methods can I use to clean sponges?

The NSF International, a public health safety organization that develops standards and certifications advocates two more methods to cleaning sponges aside dish washing, and none of the method uses detergent in a hot soapy water. It just doesn’t work as good.

Here are the two other methods.

Use the microwave:

The microwave is one of the best ways to sanitize a sponge after use, and according to the USDA, it gets rid of up to 99.9999 percent of bacteria in the sponge, as opposed to the 99.9998 of the dishwasher. So it’s slightly more effective than it.

To clean a sponge using the microwave, you first need to soak the sponge and wring until only when it’s dampen. Then microwave for at least 2 minutes either on the turntable or on top of a microwave safe flat plate.

After that, take out the sponge and store in a place where it can dry out before next use.

Use bleach – the ultimate sanitizer.

According to many authorities, the bleach method is the most effective of the three methods for cleaning a sponge, even though they still label its efficiency the same as that for a microwave 99.999 percent. I guess the reason why is obvious, the bleach of course which naturally has bactericidal properties!

For the bleach method, you want to submerge the sponge in a bleach solution for at least 5 minutes. Then you want to take it out and rinse properly because you wouldn’t want to disinfect your intestines as well. As for the measurements, it is recommended to use ¾ cup of bleach for every gallon of water.

Frequently Asked Questions

Is it okay to put a sponge in the dishwasher?

Yes, it is perfectly safe to put a sponge in the dishwasher. In fact, the dishwasher is one of the three recommended methods by the USDA for cleaning sponges. It removes around 99.998 percent of the germs most of the time when run at the longest hottest cycle and dried.

To clean a sponge in the dishwasher, place it at the top rack and run the regular cycle. After that, place it on a sponge case (do not cover) or dish rack to further dry out.

Does microwaving a sponge kill bacteria?

Yes, microwaving a sponge does kill the bacteria present in it by a million fold according to a report published by the United States Department of Agriculture in 2009. The heat in the microwave penetrates through cervices and target bacteria that thrive in there, which are normally destroyed by heat. The process is exactly similar to the way you destroy bacteria when you cook food at high temperatures.

For microwaving sponges, a damp sponge is requisite for heating and also to prevent burning of the sponge in the microwave. Place in on a microwave safe plate and heat on high for 2 minutes. That should do the trick!

Final Verdict

Sponges can get very dirty between cleaning as many researches have pointed out, and one of the recommended ways that you can employ to sanitize them is by putting them inside the dishwasher. The heat from the water sprits attacks and kills the bacteria present in the sponge crevices 99.9998 percent of the time, which is considered safe for using on crockery.

When placing sponges inside dishwashers, ensure to place them at the top rack to prevent damage due to heat, and then run the longest, hottest cycle to up the heat game. Remember the hotter the water, the easier bacteria are killed.

As an alternative to the dishwasher, sponges can also be cleaned in the microwave by dampening them first, then microwaving for at least two minutes. Additionally, they can be cleaned by submerging in a bleach solution for at least five minutes and then washing thoroughly to remove and bleach residue, which when ingested can be detrimental. .

Despite all these methods for sanitizing sponges, a good rule of thumb for proper hygiene is to avoid keeping sponges for longer than two weeks in the house, as then, they could be unsafe for cleaning crockery.