Germs Everywhere: How Risky is Using a Public Restroom?

Public restrooms are well-known major germ zones, and many people worry they may catch an infection when they use them. How risky is using a public restroom, really? Let’s find out.

Key takeaways:
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    Various bacteria and viruses (including Coronaviruses) lurk around toilets and other surfaces in a public restroom.
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    Although the number of microbes in restrooms is extremely high, many of these bacteria quickly die, and the risk of catching an infection is very low.
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    Everyone should use good hygiene practices.

While restrooms usually account for only 5% of a building’s total space, they carry almost 40% of a facility’s total soil load. More importantly, the germs found in the restroom can also cause various infections and illnesses.

How many bacteria are in a public restroom?

Jack Gilbert, a researcher and microbiologist at Argonne National Laboratory in Illinois, conducted special studies to better understand the safety of public restrooms. According to Gilbert, people bring a lot of bacteria in the restrooms, more than most would expect. According to one study, scientists found an average 500,000 bacterial cells per square inch on various bathroom surfaces.

Could the microbes from public restrooms actually cause infections?

Although the number of microbes in restrooms is extremely high, many of these bacteria, particularly gut bacteria eliminated in feces, quickly die. This is because gut bacteria thrive in the lower digestive tract which is warm, moist, and provides nutrients for them. On the other hand, gut bacteria do not tolerate oxygen or the cold, dry environment found on the surface of toilets, floors, and fixtures in a restroom. These microbes are detected in higher amounts on the toilet handles and seats, likely from contamination from feces or from toilet spray.

Bacteria commonly found on the skin, such as Staphylococcus aureus, are more adapted to survive in a restroom and can persist on surfaces for a long time. These microbes are more common on the doors, stalls, faucets, and soap dispensers. While these bacteria are unlikely to cause problems in healthy individuals, those who have open wounds or a weakened immune system should be more cautious.

One study conducted by Cocoon, an Australian manufacturer of protective coatings, evaluated some of the most common types of bacteria found on toilet seats in public restrooms. The list includes:

  • Corynebacterium, which are linked with diphtheria and hepatitis (found on over 80% of toilets tested in the study)
  • Streptococcaceae, which can cause pneumonia and sore throat (found on almost 40% of toilets tested)
  • Pseudomonadaceae, which can cause urinary tract infections (found on over 20% of toilet seats)
  • Enterobacteriaceae, which are linked with kidney and gut infections (found on almost 20% of toilet seats)

Viruses like hepatitis A can, in theory, be transmitted in a restroom if an individual touches a contaminated surface and then his mouth without cleaning his hands first. Most Americans are vaccinated for hepatitis A early in life, but it is still important to practice good hand hygiene!

Tests conducted in laboratory settings suggest that flushing a toilet with the lid open could become a source of infection because clouds of bacteria droplets that can rise about 3 feet from a flushing toilet can be inhaled by the next person using the toilet. However, this theory was not confirmed, because there are no reports of a disease that was transmitted this way.

The overall conclusion is that the microbes found in a restroom have a very low probability to cause an infection, and the chances are even lower for those who use good hygiene practices.

How to safely use a public restroom

  1. Keep your hands clean. Wash them with soap and warm water for at least 20 seconds. If this is not an option, use hand sanitizer containing a minimum concentration of 60% alcohol.
  2. Try to maintain some distance from other people during your trip to the restroom.
  3. Use wipes and tissues to cover your hands when touching faucets, stall doors and toilet paper dispensers.
  4. Dry your hands. If you use a paper towel, do not throw it in the garbage, but use it on the door handle and discard it on the other side.
  5. Get in and out of the restroom as quickly as possible.
  6. Avoid using your cell phone in the restroom. The phone also carries a lot of germs and using it in the restroom increases the risk of transferring microbes from the toilet to the phone, and later to the mouth and nose.

Using a public restroom during the pandemic

The COVID-19 pandemic has added another layer of risk, as health experts continue to monitor the risk of viral transmission in public settings like restrooms. Like other microbes, research found that SARS-Cov-2 virus from an infected person’s stool could be found on toilets or may linger in the air nearby.

In addition to using good hygiene practices and following the guidelines from public health officials, anyone who wants to increase safety in a public restroom could wear a mask. Toilets with lids can be closed before flushing to avoid the clouds of bacteria.

Whether air dryers are a safer option compared with paper towels remains controversial. Some studies suggest that air dryers may blow dangerous microbes around, while others believe that air dryers will disperse the air, decreasing the risk to get enough viral particles to infect a person.

To prevent COVID-19, the Centers for Disease Control and Prevention (CDC) also recommends hand washing with soap and water for 20 seconds after leaving a public place, touching your mask, or using objects or surfaces that may be frequently touched by other people (i.e., door handles, gas pumps, shopping carts, or electronic cashier screens) and before touching your eyes, nose, or mouth.

While public restrooms are loaded with various disease-causing microbes, the chances of actually getting an infection in these places is very low. You can further lower these chances if you follow good hygiene practices.