On a scorching summer day, a swimming pool may seem like the perfect escape, but water-quality experts and infectious disease doctors caution that common hygiene mistakes can turn a refreshing dip into a health risk. While chlorine is an effective disinfectant, it does not work instantly or eliminate all pathogens, and many swimmers unknowingly contribute to contamination through everyday habits.
One of the most widespread misconceptions is that chlorine kills germs the moment they enter the water. According to Kelly Reynolds, an environmental microbiologist at the University of Arizona, chlorine kills ordinary bacteria within a minute of direct contact. However, viruses like hepatitis can survive for about 15 minutes, and the parasite Cryptosporidium — the leading cause of pool outbreaks in the United States — can live in chlorinated water for roughly 10 days. To eliminate Crypto, pool operators must shock the water with about 20 times the usual chlorine concentration, a process that takes hours. Reynolds notes that many people treat pool water as a sanitizing liquid, but with only about one part chlorine per million parts water, it is far weaker than hand sanitizer, which is roughly 60% alcohol.
Another common mistake is skipping the pre-swim shower. Most swimmers do not rinse off before entering the pool, but a quick 30-second shower can wash away sweat, sunscreen, body oils, and traces of fecal matter, reducing the load of contaminants introduced into the water. Lisa Cuchara, a professor of biomedical sciences at Quinnipiac University who teaches a course on recreational infections, emphasizes that showering before swimming helps keep the pool cleaner, while showering afterward protects swimmers from picking up germs and prevents chlorine from drying out skin and hair.
Swimming with open wounds also poses risks. Dr. Daniel Egan, an infectious disease specialist at Orlando Health, explains that chlorine reduces but does not eliminate the risk of infection when skin is broken. A small cut may not be a major concern, but large abrasions or surgical incisions expose the body to potential pathogens. He advises using a waterproof dressing, such as Tegaderm, before entering the pool and replacing it with a fresh dressing afterward. Patients who have recently undergone surgery should obtain clearance from their doctor before swimming, even after stitches are removed.
Foot hygiene is often neglected, yet feet are among the body's highest-bacteria zones, along with the face, underarms, groin, and hands. Dr. Alok Vij, director of dermatologic surgery at Vitalogy Skincare in Austin, notes that most people do not wash their feet thoroughly, and research shows that washing feet with soap twice a day significantly reduces bacterial load. One common bacterium, Pseudomonas, thrives in under-sanitized pools and can cause swimmer's ear, meaning that a classic summer ear infection may originate from someone's unwashed feet. Vij stresses the importance of giving feet proper attention in the shower, especially before swimming, and warns that sand from the beach can clog pool filters, impairing the pool's ability to clean itself.
Urinating in the pool is another habit that many dismiss as harmless but is actually problematic. Cuchara explains that urine reacts with chlorine, depleting the disinfectant and producing chloramine, the chemical responsible for the strong «pool smell» that often irritates eyes and respiratory systems. This reaction reduces the chlorine available to kill germs, increasing the risk of waterborne illness.
Experts advise swimmers to adopt simple preventive measures: shower before and after swimming, avoid entering the water with open wounds, wash feet thoroughly, and refrain from urinating in the pool. By following these guidelines, swimmers can help maintain cleaner water and reduce the likelihood of infections, making the pool a safer place for everyone.
