Science

If you can smell chlorine in the pool, bad news: it has nothing to do with hygiene or cleanliness

The summer heat makes people long for a refreshing dip at the local pool. However, before you jump you’ll want to know this about the “clean” pool smell.

Claudia Sánchez Greg Heilman

Update: Jul 9th, 2025 12:57 EDT

For decades, we’ve associated the sharp smell of chlorine with cleanliness—proof that a pool is properly disinfected and safe. But according to recent scientific findings, that telltale scent may actually signal the opposite: your pool could be filled with contaminants.

Why that strong chlorine smell is actually a red flag

If you walk past a pool and immediately catch a strong whiff of chlorine, it’s not because the water is extra clean. In fact, the odor is caused by a chemical reaction between chlorine and nitrogen-based substances introduced by swimmers—mainly from urine, sweat, and body oils.

The result? A compound called chloramine, which is not only irritating but also potentially harmful. The stronger the smell, the higher the concentration of these pollutants—and the more the pool’s disinfectant is working overtime to combat them.

How chloramines affect your health

Ever left a pool with red, itchy eyes or irritated skin? That’s not chlorine doing its job—it’s chloramine wreaking havoc. This toxic byproduct can trigger eye and skin irritation, worsen respiratory conditions, and even reduce air quality around indoor pools.

Worse yet, chloramines aren’t very effective at killing germs. So, while they smell strong, they’re actually a sign that the pool water may not be properly sanitized.

The real hygiene heroes: showering and pool etiquette

To reduce chloramine levels, experts stress the importance of basic hygiene rules—rules too often ignored:

Always shower before entering the pool.
Never urinate in the water, no matter how tempting.
Avoid swimming if you’re sick, especially with gastrointestinal symptoms.

These simple actions can significantly reduce the amount of organic waste introduced into pool water, making the disinfectants more effective—and helping everyone breathe a little easier.

What a clean pool should actually smell like

Here’s the surprising truth: a properly maintained pool should barely smell like chlorine at all. That overpowering “clean pool” scent? It’s a myth—and one that could be masking dangerously high levels of contamination.

When pools are well-balanced and properly disinfected, the water should be crystal clear and nearly odorless. So, if the smell makes your eyes water before you even dive in, it might be time to question how well that pool is really being maintained.

Bottom line: Don’t let the smell fool you

Pool care isn’t just about keeping the water looking good—it’s about protecting public health. And while chlorine is essential for killing harmful bacteria, viruses, and fungi, it can only do its job if swimmers do theirs, too.

Next time you’re tempted to skip the shower or ignore that urge to use the restroom, remember: you’re not just affecting your own experience—you could be helping turn that refreshing swim into a chemical soup.