How to Avoid Pool Germs When Swimming in Public Pools

On sweltering summer days, there are few pleasures as cooling as a swim in a pool. Yet, have you considered whether the water is really as clean as its clear blue appearance suggests?

As an immunologist and infectious disease specialist, I examine how germs circulate in public settings and ways to stop their transmission. I also run a course entitled "The Infections of Leisure", in which we look at the hazards linked to recreational pursuits and the precautions available, without making students overly fearful of germs.

Swimming, particularly at public pools and water parks, brings a distinct range of risks, from mild skin irritation to gastrointestinal illness. At the same time, it offers a wealth of physical, social and mental health benefits.

A little awareness and sensible care can help you make the most of the water without dwelling on what could be beneath its surface.

The truth about pool germs

Summer headlines and social media regularly draw attention to the "ick-factor" of shared swimming venues. There is some justification for these worries.

Chlorine, the disinfectant commonly used in pools, is good at destroying many pathogens. However, it does not act immediately, nor does it eliminate every germ.

Each summer, the Centers for Disease Control and Prevention publishes warnings about outbreaks of illness associated with exposure to germs in public pools and water parks.

A 2023 CDC report recorded more than 200 pool-related outbreaks across the US between 2015 and 2019, affecting over 3,600 people. These incidents involved skin infections, respiratory problems, ear infections and gastrointestinal upset. Although many infections of this kind have mild effects, some can be severe.

Pool germs and disinfectants

Some pathogens can remain in the water for anything from minutes to days, even when a pool has been correctly chlorinated.

Among the most frequent offenders is Cryptosporidium, a microscopic germ responsible for watery diarrhoea. The hardy outer shell of this single-celled parasite enables it to persist in chlorinated water for as long as 10 days. It is transmitted when faecal matter, commonly from a person with diarrhoea, gets into the water and is then swallowed by another swimmer. A very small amount, even one that cannot be seen, may infect dozens of people.

Pseudomonas aeruginosa is another widespread germ, a bacterium behind hot tub rash and swimmer's ear. Pool water can also retain viruses such as norovirus and adenovirus, which can cause illness.

People swimming introduce many bodily substances into the water, including sweat, urine, oils and skin cells. When these materials, particularly sweat and urine, react with chlorine, they create chemical byproducts known as chloramines, which may carry health risks.

Those byproducts cause the powerful chlorine odour often associated with pools. In reality, a clean pool should not have a strong chlorine smell, or any other odour. The belief that a pronounced chlorine scent signals a clean pool is a common myth. Instead, it can be a warning sign of the reverse: contaminated water that may be best avoided.

Staying safe at a public pool

Straightforward measures by pool staff and swimmers can lower most risks associated with pools. Most pool-related illnesses will not be fatal, but nobody wants to spend a holiday, or a week of glorious summer weather, in the bathroom.

These 10 measures can help you steer clear of germs at the pool:

• Have a shower before entering the pool. Rinsing for at least one minute removes most body dirt and oils, which can otherwise make chlorine less effective.
• Stay out of the pool when you are unwell, particularly if you have diarrhoea or an open wound. Germs spread rapidly in water.
• Keep pool water out of your mouth where possible, reducing the chance of swallowing germs.
• Do not swim while you have diarrhoea, as this helps stop germs from spreading.
• If you are diagnosed with cryptosporidiosis, commonly known as "crypto," do not return to the pool until two weeks after the diarrhoea has stopped.
• Go to the toilet regularly. Frequent bathroom breaks for both children and adults reduce the likelihood of accidents in the pool.
• Inspect nappies every hour and change them away from the pool to avoid faecal contamination.
• Thoroughly dry your ears after a swim to reduce the risk of swimmer's ear.
• Avoid swimming with an open wound. If you must do so, ensure it is fully covered by a waterproof dressing to protect yourself and other swimmers.
• Shower after swimming to wash germs off your skin.

Lisa Cuchara, Professor of Biomedical Sciences, Quinnipiac University

This article is republished from The Conversation under a Creative Commons license. Read the original article.