Pool Chlorine Scent Exposed: Urine and Sweat Create the Real Stench

Scientist Reveals the Stomach-Churning Truth About Chlorine Smell in Swimming Pools
By Xantha Leatham, Executive Science Editor
Published: 10:21 BST, 24 July 2025 | Updated: 10:21 BST, 24 July 2025

Substances like sweat and urine in pools react with chlorine to form chloramines, creating health risks (File Image).

Planning a refreshing dip this summer? Public pools and water parks might seem inviting, but they can harbor dangerous germs causing diarrhea, rashes, and infections, warns microbiologist Lisa Cuchara. Even chlorinated pools aren’t foolproof—pathogens like Cryptosporidium, Pseudomonas aeruginosa, norovirus, and adenovirus can linger.

The Hidden Dangers in Pool Water

Cryptosporidium, a parasite causing severe gastrointestinal illness, thrives in poorly maintained pools. Spread via fecal contamination, it can infect swimmers for weeks. “Even a tiny, invisible amount of fecal matter can sicken dozens,” says Cuchara.

Pseudomonas aeruginosa is another culprit, leading to “hot tub rash” (itchy, red bumps) or “swimmer’s ear,” an ear canal infection. Norovirus and adenovirus add to the risks, triggering stomach bugs and respiratory issues.

Cryptosporidium, a leading cause of pool-related illnesses, can survive chlorination (File Image).

The Chlorine Myth

A strong chlorine smell doesn’t guarantee cleanliness. Chloramines—chemicals formed when chlorine reacts with sweat, urine, or feces—create that odor. “A clean pool shouldn’t smell harshly of chlorine. That scent actually signals contamination,” explains Cuchara.

How to Stay Safe

Shower before and after swimming.
Avoid swallowing pool water.
Don’t swim with diarrhea or open wounds.
Dry ears thoroughly post-swim.
Check children’s diapers hourly.

Showering after swimming helps remove lingering germs (Illustrative Image).

Public pools remain hotspots for waterborne diseases, with England and Wales reporting frequent outbreaks. By staying vigilant and following hygiene tips, swimmers can reduce risks and enjoy a safer splash this summer.

Source: Professor Lisa Cuchara, Quinnipiac University