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There are a number of ways germs can grow on your shower curtain, but experts say most of them aren’t a serious health threat for most people. Getty Images
  • A study by a research company says your shower curtain probably has the most germs of anything in your bathroom.
  • Experts say the germs and bacteria that grow on a shower curtain aren’t a serious health threat to most people.
  • Experts also say you should still properly clean your shower curtains on a regular basis.

You may be showering in harmful bacteria, but it doesn’t come from your tub or the shower nozzle.

It may be from your shower curtain.

So says a study conducted by Safe Home, a research and review company located in Los Angeles.

Their researchers tested three shower curtains and surveyed more than 500 people.

The culture analysis detected upward of 60 times more microbial life on shower curtains than toilet seats.

This suggests shower curtains are the dirtiest surfaces in the bathroom.

The strains of bacteria present include gram-negative rods and gram-positive rods.

The study authors say the majority of gram-negative rods are harmful to humans and can be resistant to antibiotics.

Healthline spoke with experts to determine the cause and severity of the risks associated with unsanitary shower curtains and what you should do to keep your curtain clean and family healthy.

According to the study, Americans are doing much more in the shower than washing and rinsing.

Study participants reported the following shower activities:

  • urinating (81 percent of men and 73 percent of women)
  • having sex (61 percent of people)
  • shaving (65 percent)
  • brushing teeth (33 percent)

While these habits undoubtedly add to the reasons for regularly cleaning our showers, experts say there is no strong evidence to support that any of them cause higher levels of bacteria on shower curtains.

Bacteria from fecal matter, though, can spread from the toilet to the curtain — and your toothbrush — by way of the toilet’s plume, or its spray radius, say experts.

Keeping your toilet seat closed when flushing helps prevent the spread of germs.

After these germs collect on your shower curtain, the different bacteria multiply in the hot, humid, and often dark environment of your shower.

Experts say the bacteria survive and even thrive on organic compounds released from our bodies through coughing, burping, and other bodily functions.

Charles P. Gerba, PhD, a microbiologist and professor at the University of Arizona, told Healthline that while bathroom bacteria hasn’t been well-studied, it also hasn’t been associated with well-documented risks in healthy persons.

“Some opportunistic pathogens have been detected, but for healthy persons, it should not be a problem,” he said.

Commonly found opportunistic pathogens include sphingomonas and methylobacterium.

While these organisms can infect wounds and exacerbate illness in people with compromised immune systems, experts agree that shower curtain bacteria isn’t a threat to private households.

“There is good news when it comes to shower curtains,” Dr. Jeffrey Brown, a family medicine specialist at the Cleveland Clinic in Ohio, told Healthline.

Brown points to a study, published in 2004 in the journal Applied and Environmental Biology, showing that 80 percent of the bacteria on your shower curtain comes from two types of bacteria.

These types of bacteria differ from those most recently found.

“One [strain] typically only causes infection in very rare cases and, even then, it tends to be in people admitted to the hospital with a compromised immune system,” he said. “For example, those being treated for things like cancer, autoimmune diseases, or HIV.”

“The other bacteria is the one responsible for body odor. Although it may not be desirable, it’s certainly not harmful,” Brown added.

Brown notes that “there were small amounts of E. coli, which causes diarrhea.”

The Safe Home study did not look for fecal bacteria such as E. coli, but nevertheless, the cause for worry is low.

“It’s still very unlikely you would catch an E. coli infection from the shower curtain as it needs to be ingested,” Brown said.

Rather than worry about bacteria in the bathroom, Gerba suggests we turn our attention toward mold.

“Mold seems to be the major problem,” Gerba said. “I think most of the risk is from mold allergies and sharing the shower among family members.”

While bacteria and mold are not to be confused, they both similarly thrive in washroom environments.

According to the National Institute of Environmental Health Sciences, mold exposure is associated with health concerns such as eye irritation, chronic cough, skin rashes, and sore throat.

Children, older adults, and people with compromised immune systems are more vulnerable to the risks.

Experts suggest you clean your shower curtains with regular frequency to prevent bacteria and mold growth.

Exact cleaning depends upon your household’s shower habits.

“It depends on how much use your shower is getting,” said Becky Rapinchuk, author of “Clean Mama’s Guide to a Healthy Home.”

Rapinchuk advises we clean our curtains monthly or at least quarterly if the shower is getting daily use.

To keep things simple, she prefers to use a fabric shower curtain liner.

“It can be laundered and dries much quicker than a traditional or plastic/PVC liner,” Rapinchuk told Healthline.

Experts say plastic and vinyl curtains are also more prone to accumulating biofilms or layers of microbial life that we call “soap scum.”

But don’t worry.

“Either way, both are washable,” said Rapinchuk. “Just toss in the washer with your favorite detergent and wash on cold.”

After washing, she said, “Line dry if it’s plastic and tumble dry if it’s fabric.”

Rapinchuk has another tip, one to use after you shower.

“Close the shower curtain so it doesn’t bunch up and so it can fully dry,” she said.

You can also mist your shower’s surfaces with a cleaner between deep washes.

Rapinchuk shares her original recipe.

She says to mix the following ingredients in a spray bottle and spray your shower walls and curtain after showering:

  • 1/2 cup vodka
  • 1 cup water
  • 10 drops peppermint essential oil

Proper ventilation in your washroom is also important, she noted.

Sometimes it’s better to start with a fresh shower curtain and commit to a new cleaning schedule.

Jennifer Rodriguez from Pro Housekeepers said, “If you don’t wash your shower curtain for several months, you’re likely going to get mildew that could cause some health issues.”

“If there is mold or mildew on your shower curtain, toss it out,” said Rapinchuk. “If the material is worn or breaking down, toss it.”

Experts say mold in the home typically appears blackish, bright red, or green, whereas mildew is grayish-white or yellowish in appearance.

“When you see nasty grime buildup that doesn’t go away, the best practice is [to replace your curtain] once per year,” Rodriguez said. “Some people like to alternate shower curtains throughout the seasons, and this helps them last much longer.”

Rodriguez says adding white vinegar to the cold water wash cycle can help further break down grime.

She also suggested avoiding harsh chemicals when washing and skipping bleach with sensitive fabrics and colored items.

“For both natural and synthetic fabrics, use only mild detergent and some white vinegar,” Rodriguez said.