(CNN)There is nothing like wrapping yourself up in a fluffy, warm towel after a hot shower or bath.
After drying yourself, however, the towel also gets wet. Now it's the perfect home for germs. Hopefully you're hanging it up to dry, but that doesn't keep your towel clean.
That's why CNN turned to an expert to learn how often towels should be washed to prevent them from getting us dirty, which is the exact opposite of its intended use.
Wash your towels at least once a week. That's the rule of thumb that Manal Mohammed, senior lecturer of medical microbiology at the University of Westminster in the United Kingdom, recommended.
Can I reuse a towel after one use?
Reusing towels a few times is better for the environment and likely won't be a cause for alarm. But as soon as you notice any funky smells, it's definitely time for a wash, since this is an indication of fungal and bacterial growth, Mohammed said.
"Towels are not clean as you think and can transmit germs," Mohammed said.
And during the pandemic, anyone infected by Covid-19 in your home should use separate towels.
"It is not known how long coronavirus can survive on towels, but it is very important not to share towels with infected people or self-isolating people at the household," Mohammed said.
How do germs end up on towels?
Every time you use or touch a towel, you transfer any germs on your body to that towel. That's why it's recommended -- even before the pandemic -- to wash your hands with soap and water for 20 seconds.
"If you do not wash your hands properly -- for at least 20 seconds -- especially after using the toilet, as it is full of germs, these can easily be transferred to your towel," Mohammed said.
And our towels can even get dirtier in the wash if not done properly.
Washing towels with high-risk items such as underwear, which is more likely to hold traces of feces or bacteria from genital infections, can increase the chances that our towels aren't as clean as we'd like them. For this same reason, towels should never be washed with items heavily soiled with bodily fluids such as vomit.
Just like proper washing is important for a clean towel, so is proper drying after use. Not allowing towels to fully dry can create an excellent environment for bacterial growth.
"Damp, used towels in moist bathrooms encourage microbial growth," she said. "Although most of these germs are often harmless, some of them (including Staphylococcus bacteria) can cause infection and health problems, especially in people with skin wounds and immunocompromised people."
How dirty do our towels really get?
Fungi, including the pathogen that causes tinea cruris (jock itch), can spread through shared towels, according to Mohammed. Dermatophytic fungi, such as those that cause athlete's foot, can cause infections in cuts or sensitive skin.
"Do not get excited when athletes throw their towels at you!" said Mohammed.
Some infections can be even more serious, such as Staphylococcus bacteria. While it normally lives on our skin, if bacteria enters through a wound, the infection that results is resistant to antibiotics.
Towels can also spread bacteria that cause acne. Mohammed advises avoiding this by not sharing towels with others. Pink eye, or conjunctivitis, can also spread since the fabric comes into contact with the face and eyes.
Since towels are kept right next to one of the germiest places in your home, the toilet, it shouldn't be the biggest surprise that sometimes what we flush ends up on our towels. Coliforms, such as E. coli, can transfer to towels because of this.
These bacteria normally live in our gastrointestinal tract and are associated with fecal matter and can cause food poisoning and urinary tract infections.
Washing kitchen towels separate from bathroom towels also reduces the risk of bacteria spreading.
A 2014 study of kitchen hand towels found that 89% were home to coliform bacteria and 25% had E. coli. The towels were collected from households in five major cities in the United States and Canada.
Keeping towels clean
To start, don't share towels whenever possible. Those towels that are shared, such as hand towels, should be replaced with a clean towel