The 13 Dirtiest Things in Your Home, According to Science

These are the germ-infested items you should clean frequently to stay healthy.

No matter how often you hit your home with a bottle of Lysol or a container of Clorox, it's still likely teeming with germs. And while that truth was easy for some of us to ignore in the past, the coronavirus pandemic has even casual cleaners concerned about all the items and surfaces they and their families touch. That's why we've compiled a list of the dirtiest things in your home that you can—and should—focus on the next time you break out the disinfectant.

While this study happened in 2015, well before COVID-19 began to spread, researchers at the University of Colorado at Boulder collected dust samples from 1,200 American households and were able to identify more than 9,000 different species of microbes, bacteria, and fungi. Put simply, there's a huge amount of germs hidden on your doorknobs and under your couch cushions.

Though the best course of action would be to do a deep clean of your house every week, it's admittedly unrealistic, even if you are working from home right now. When you do go through your regular cleaning ritual, make sure to hit the following 13 spots with a sanitizing cleanser or otherwise change them out frequently:

1. Your Computer Keyboard

Typing on a Computer Keyboard Dirtiest Things in Your Home

Given how much time the average American spends on their computer—approximately 6.5 hours a day at work alone, according to one 2018 survey from Acuvue—it's little surprise that our keyboards are brimming with germs.

In fact, one 2018 study published in the International Journal of Environmental Research and Public Health tested various keyboards and found that the majority of them were infected with strains of bacteria ranging from Bacillus to Staphylococcus aureus, which each have the potential to cause disease.

2. Your Kitchen Sponge

Dirty dish sponge Dirtiest Things in Your Home

If you're not switching out your kitchen sponge every week or so, then you might want to start. Why? Well, one 2017 study published in the journal Scientific Reports analyzed the bacterial microbiomes on 14 kitchen sponges. The researchers found that they contained 362 different bacterial species. "Locally, the density of bacteria reached 54 billion per square centimeter of sponge tissue, which is similar to the microbial density of stool samples," study author Markus Egert of Furtwangen University explained to Popular Science. Now that's disgusting!

3. Your Cell Phone

cell phone games Dirtiest Things in Your Home

Your cell phone is easily one of the dirtiest things in your home. One 2009 study published in the Annals of Clinical Microbiology and Antimicrobials tested the phones of 200 healthcare workers and found that 31.3 percent were contaminated with gram-negative strains of bacteria.

But it gets worse: According to the National Institute of Allergy and Infectious Diseases, certain types of gram-negative bacteria have become increasingly resistant to available antibiotic drugs. So you'll want to wipe down your smartphone stat!

4. Your Bathroom Sink

Bathroom Sink Dirtiest Things in Your Home

The place in the bathroom where you go to clean your hands is also one of the dirtiest places in your home. Yes, we're talking about the sink. Believe it or not, when Mira Showers hired Marco Mendoza Villa, PhD, a researcher from the School of Biological Sciences at Bristol University, to test various bathroom surfaces for bacteria in 2018, he found that the sink was the most germ-infested. Per the study's findings, almost 80 percent of the sink's surface was covered in pathogens, making it the dirtiest area in the bathroom (even when compared to the toilet seat).

5. Your Pillowcase

Top view of attractive young woman sleeping well in bed hugging soft white pillow. Teenage girl resting, good night sleep concept. Lady enjoys fresh soft bedding linen and mattress in bedroom


When you finally have the chance to lay down at night, the last thing you want to worry about is how many germs are living on your pillowcase. However, if you aren't cleaning it at least once a week, then you can guarantee that it's anything but clean. According to 2016 research conducted by Amerisleep, a one-week-old pillowcase is teeming with an average of 3 million colony-forming units of bacteria per square inch (CFU/sq. in.). (For reference, that's 17,442 times more bacteria than what you'd find on your toilet seat.) Leave your pillowcase unwashed for three weeks, and you could be dealing with as many as 8.51 million CFU/sq. in.

6. Your Kitchen Towels

woman drying dishes, energy

When researchers from the University of Mauritius analyzed 100 kitchen towels after one month of use, they found that approximately half of them were carrying some sort of bacteria. What's more, the towels taken from bigger households tended to have more bacteria growth than those taken from small households sans children.

7. Your Toothbrush Holder

Toothbrush holder in the bathroom Dirtiest Things in Your Home

The handy dandy holder that's housing your toothbrush is probably also housing more germs than you realize. In 2011, NSF International swabbed 30 everyday items in 22 different households and found that approximately 27 percent of all toothbrush holders tested positive for Coliform, a class of bacteria that includes dangerous strains like E. coli and Salmonella.

8. Your Kitchen Sink

washing glass in a sink Dirtiest Things in Your Home

Your toothbrush holder isn't the only thing harboring Coliform bacteria. The same 2011 study from NSF International found that approximately 45 percent of the kitchen sinks tested were housing the malicious microbe as well.

9. Your Coffee Machine

coffee machine, coffeemaker, cleaning tips

Your daily cup of coffee could be providing you with much more than just a jolt of caffeine. One 2015 survey published in the journal Scientific Reports analyzed 10 Nespresso machines and found that every single one contained some sort of bacterial community. Specifically, each machine contained anywhere from 35 to 67 different bacteria genera in its drip tray alone.

10. Your Water Bottle

Man Taking a Break From His Run to Drink Some Water Dirtiest Things in Your Home

If you think that you don't have to clean your reusable water bottle just because the only thing that ever goes in it is water, think again. Per one 2017 study published in the Annals of Civil and Environmental Engineering, the average water bottle contains as much as 75,000 bacteria counts/mL—and if left dirty, that number can multiply to up to 2 million counts/mL within just one day.

11. Your Cutting Board

chopping onions on a plastic cutting board things you should clean every day

Be extra careful the next time you clean your cutting board. Per one 2006 review published in the Journal of AOAC International, cutting boards—particularly those with knife scars from intense onion-slicing sessions—are "very difficult to clean and disinfect" and have the potential to harbor bacteria like Salmonella.

12. Your Shoes

man putting on converse shoes while wearing a suit

Your parents knew what they were talking about when they told you not to wear your shoes inside the house. One 2016 study published in the journal Open Forum Infectious Diseases found that approximately 26.4 percent of all shoe soles carry C. difficile, a dangerous bacteria strain that can cause intense (and potentially fatal) diarrhea.

13. Your Remote Control

Man using a Remote Control Dirtiest Things in Your Home

Even if you don't use your television all that often, it's more than likely that your remote control is one of the dirtiest things in your home. For one 2012 study published by the American Society for Microbiology, researchers swabbed the surfaces of several objects found in hotel rooms and discovered that remote controls were one of the most germ-infested things in the room.

Additional reporting by Sage Young.

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