You’re Probably Not Washing Your Beach Towel Enough — Here’s The Gross Reason You Should Care

Summer travels often mean beach time, with everything that this entails: from salt and sand to chlorinated pool water, sunscreen, sweat and everything in between.

Dirty towels can be a quiet cause of trouble for those with sensitive skin, exacerbating conditions like acne and eczema. So, how bad can it get when we leave our beach towels and pool towels unwashed for days?

Humidity, sweat, sunscreen and sand are the perfect breeding ground for bacteria, and moisture plays a big role in microbial growth. Bacteria need water to grow, according to Dr. Joseph Battistelli, an associate professor of biology at Virginia Commonwealth University.

So, how often should we wash our beach towels on vacation, and what factors contribute to this calculation? HuffPost spoke to four experts on bacteria to get some answers.

“A towel that’s been used multiple times, especially when it’s stayed damp, becomes a breeding ground for bacteria,” said Dr. Hannah Kopelman, a board-certified dermatologist at Kopelman Hair Restoration.

“The most common bacteria found on beach towels are: Staphylococci, Micrococci and Diphtheroids (Coryneforms), in addition, environmental bacteria from sand and water would also be found on beach towels left unwashed,” explained Megan Meyer, a science communications consultant with a Ph.D. in microbiology from the University of North Carolina at Chapel Hill.

Mayer said beach sand also includes these common types of bacteria: Escherichia coli (E. coli) and enterococci, Salmonella spp., Campylobacter spp., Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA).

“Under ideal [for bacterial growth] conditions, E. coli populations can double every 20 minutes. Microbial growth on a beach towel would be much slower than this because it is not an ‘ideal’ environment,” Battistelli said.

“A lot of pathogens are what we call ‘opportunistic pathogens,’ he continued. “They are native members of our skin microbiome and don’t normally do us any harm. However, if we are injured, immunocompromised, or transfer the bacteria to a new person, especially an at-risk person, then the bacteria can take advantage of the opportunity to cause infection. Towels can harbor yeasts and fungi, too,” he added.

“I’ve seen everything from folliculitis to ringworm in patients who’ve reused moist, unwashed towels, especially after sweating or swimming. Fungi and bacteria thrive in damp, warm environments, and a rolled-up beach towel can be just that. If you have any cuts, shaving nicks, or even inflamed hair follicles, bacteria can sneak in and cause an infection. It can become a medical issue,” explained Kopelman.

“The difference between using a towel after the beach versus after a shower at home will mainly result in differences in microbial profiles. It’s important to note that beach sand often contains fecal bacteria from wildlife, runoff contaminants or toxins, and microplastics,” said Meyer.

When using a towel at home, the bacteria present are different. “I would expect the towel [at home] to mostly have skin-associated bacteria since the towel was used to dry off a person,” said Battistelli.

The type of water exposure also matters. “Ocean water contains salt, which tends to inhibit bacterial growth. Towels used briefly after a swim in clean saltwater may remain relatively clean. However, freshwater environments, like lakes or rivers, are more likely to harbor bacteria, fungi, or other microbes, particularly in warm, stagnant conditions,” said Prodanovich.

For pools, it’s not always as clear-cut since the temperature and the concentration of chlorine or other disinfectants play an important part in bacterial growth.

If you have conditions like eczema or athlete’s foot, this can increase the likelihood of infections, especially with habitual reuse of unwashed towels, Prodanovich said.

The skin on the body can be severely impacted by an unwashed towel. “I’ve seen patients develop acne-like breakouts or flare-ups of eczema simply from using dirty towels. Towels trap sweat, oils, dead skin, and bacteria; all of which can irritate sensitive skin and clog pores,” explained Kopelman.

For acne-prone people, towels that are used on the body can reintroduce acne-triggering bacteria. Kopelman encourages her patients to change towels and pillow cases quite often for similar reasons.

“If you have sensitive skin or eczema, the risk or irritation is heightened, as the skin barrier may already be compromised. In those cases, even mild microbial buildup can lead to inflammation or flare-ups,” said Prodanovich.

Avoid sharing towels with others, as this can spread fungal infections like ringworm or athlete’s foot, especially if you have any abrasions or open wounds that come in contact with the towel; this can be a recipe for disaster.

“I wouldn’t recommend it, especially if you are immunocompromised or have other ailments that put you at risk for infection,” agreed Battistelli.

It really does, explained Meyer: “Research has shown that bacteria can survive nearly 2.5 times longer on synthetic fabrics like polyester or microfiber, compared to cotton towels. It’s also been shown that bacteria stick more to fabrics like polyester and, therefore, are more active in polyester towels.”

There are some warning signs, like the odor (musty or sour smell) and texture (stiffness or slimy texture), that your beach towel is overdue for a wash. “If your towel smells even slightly musty, has any stiffness to the fabric, or feels damp hours after use, it’s time to wash it. That musty smell is often mildew or bacterial overgrowth,” said Kopelman.

“And if it’s been sitting in a beach bag for hours, even if it seems dry, it may still be loaded with microbes,” she added.

“Realistically, I recommend washing beach towels every two to three uses at most, but ideally daily, especially if you’re lying on it, sweating, or it stays damp for long periods,” noted Kopelman.

“I would wash the towel every day or get a fresh towel between beach sessions,” said Battistelli.

“If possible, use a fresh towel daily, or at a minimum every other day, and allow it to air in direct sunlight and dry fully. Choose 100% cotton towels for their superior breathability and natural antimicrobial qualities,” said Meyer.

Per the experts, the ideal scenario is washing your towel every few days, or even daily. This might not be possible on vacation, so there are a few alternatives experts recommend.

First, shake out sand and any debris after use. Then leave the towel to dry in the sun when possible, as UV exposure can help decrease bacterial growth. “UV rays have natural antimicrobial effects, so laying your towel out in direct sun is better than leaving it bunched up,” noted Kopelman.

“Hang the towel fully stretched out in a well-ventilated area or direct sunlight,” agreed Prodanovich. Before you use it again, ensure the towel is fully dry.

Note that if you are in a humid environment, even air-dried towels may still retain moisture that supports bacterial growth. Avoid leaving wet towels bunched up or in a bag.

“If daily washing is not practical, allowing the towel to dry thoroughly between uses and washing it every two to three uses is a reasonable compromise,” said Prodanovich.

Have one towel to lie on and one to dry yourself with, to minimize the buildup, and rotate between multiple towels, if possible, to allow more drying time.

It’s also important to wash your beach bag or tote once in a while, since “it holds damp towels and swimsuits and can become just as funky,” said Kopelman.

Finally, a habit that’s often overlooked is drying the towel completely before reuse, which is even more important than how frequently you wash them, explained Prodanovich.

Keep in mind that these are short-term fixes when proper washing is not an option. When you can wash your towels, you can add white vinegar to the rinse cycle to eliminate bacteria and odors.