What Pool Chlorine Really Does to Your Body

Chlorine gets a bad wrap.

Dry skin. Red eyes. That harsh “pool smell” people complain about the second they walk into a backyard or indoor pool.

That story is common enough, but it doesn’t really hold water. Because when a pool is dialed in properly, chlorine isn’t the thing people notice. It’s only when the chemistry starts to slip that all those issues show up.

The truth sits right in the middle—and if you’re constantly around pools, understanding that nuance matters more than most people realize.

Because while chlorine is the backbone of modern pool sanitation, it’s also one of the most misunderstood chemicals when it comes to swimming pools.

And here’s the part most people don’t really get: it’s not just about chlorine itself—it’s what happens after it starts doing its job.

Chlorine Isn’t the Problem—Until It Becomes One

Let’s start here: properly balanced chlorine is not the enemy.

In fact, it’s the reason pools are even usable in the first place. It kills bacteria, neutralizes contaminants, and keeps water safe for human use. Health authorities consistently point out that when maintained within proper ranges, it’s not associated with harmful effects.

But chlorine doesn’t exist in a vacuum.

The second it hits organic matter—sweat, sunscreen, urine, body oils—it reacts. And that reaction creates a whole different class of compounds known as disinfection byproducts, most notably chloramines.

That’s where things start to get interesting.

That “Chlorine Smell”? That’s Actually the Problem

Here’s a quick reality check you can drop on any homeowner:

Think of your pool like a kitchen.

Free chlorine is your cleaning crew.
Chloramines are what happens when that crew gets overwhelmed and starts leaving behind dirty rags instead of actually cleaning.

Here’s what’s going on in plain English:

When your pool is “healthy,” chlorine is actively killing contaminants—sweat, sunscreen, body oils, urine, all the stuff people bring into the water. When chlorine does its job properly, it finishes the job and stays effective.

But when a pool is struggling, a few things usually happen:

• Not enough chlorine
• Poor circulation
• Dirty filter
• Heavy bather load
• High heat / sunlight burning chlorine off

Now the chlorine can’t keep up.

Instead of fully destroying contaminants, it only partially reacts with them—especially nitrogen-based stuff like sweat and urine.

That partial reaction creates chloramines.

And here’s the key:
Chloramines are basically used-up chlorine that’s now weak and smells bad

So the worse your pool condition gets, the more this cycle feeds itself:

1. More contaminants enter the water
2. Not enough strong chlorine to handle it
3. More partial reactions happen
4. More chloramines form
5. Water gets cloudy, smells “chlorine-y” (ironically), and irritates eyes
6. Now your chlorine is even less effective

It’s like your cleaning crew switching from disinfectant to just wiping things around with a dirty sponge.

That “strong chlorine smell” people talk about?
That’s not clean water—that’s chloramines building up.

What It Actually Does to the Body

Let’s break it down in real-world terms—the stuff people actually feel after swimming.

Skin: Dry, Tight, Irritated

Chlorine strips natural oils from the skin. That’s not a theory—it’s literally how it works as an oxidizer. The longer the exposure, the more moisture gets pulled out, leading to dryness, itching, and irritation.

For swimmers, that shows up as:
• Dry, flaky skin
• Redness or irritation
• Worsening of eczema or sensitive skin

For pool techs? Well, it’s why their hands look like they’ve been sanding drywall for 20 years.

Eyes: Burning, Red, and Watering

Again, not chlorine itself—chloramines.

When these compounds off-gas into the air (especially in indoor pools), they irritate the eyes and mucous membranes.

That classic “red eye” look after swimming? That’s a chemistry issue.

Lungs: The One Nobody Talks About Enough

This is where things get more serious.

Chloramines don’t just sit in the water—they gas off into the air above the pool surface. In poorly ventilated environments (think indoor facilities), that exposure can irritate the respiratory system.

We’re talking:
• Coughing
• Wheezing
• Chest tightness
• That “chlorine cough” you hear about

There’s also research linking repeated exposure—especially in competitive swimmers—to increased rates of asthma and airway irritation.

Now, is your average backyard swimmer at serious risk? No.

But for those working around this stuff every single day? That’s a different conversation.

Hair: Dry, Brittle… and Sometimes Green

The dryness comes from oxidation—same story as skin.

The green hair myth? That’s actually copper oxidation, not chlorine. But chlorine is what creates the conditions that allow it to happen.

Teeth: Yeah, Even That

Long-term exposure—especially in improperly balanced water—can contribute to enamel erosion and staining, sometimes referred to as “swimmer’s calculus.”

Not common for casual swimmers, but something you’ll see in high-frequency exposure scenarios.

The Bigger Picture: It’s About Byproducts, Not Chlorine

Here’s the takeaway most people miss:

Chlorine itself isn’t what causes most of the issues people complain about.

It’s the byproducts created when chlorine has to work too hard.

That’s why poorly maintained pools feel worse—even if they technically have chlorine in them.

And it’s also why a properly balanced pool with the right free chlorine, low combined chlorine, and good circulation feels completely different.

Having A Little Know-How Comes In Handy

Everything we just talked about? It’s controllable. Not eliminated—but managed. And the folks who understand this are the ones having the best swim experience.

Here’s what actually makes a difference:

• Keeping combined chlorine low (breakpoint chlorination matters)
• Proper circulation and filtration
• Encouraging pre-swim showers (huge, underrated)
• Ventilation in indoor environments
• Regular oxidation/shocking to eliminate chloramines

Fun fact: a massive percentage of swimmers skip showering before entering the pool—which means chlorine has to burn through more contaminants, creating more byproducts in the process.

So yeah… sometimes the problem isn’t with chemistry—it’s with swimmers.

The Core Chemistry Ranges To Target

Most people aren’t chasing perfection—they’re keeping water in a range where it behaves consistently. In a typical chlorine pool, that means maintaining free chlorine around 2–3 ppm, keeping pH in the 7.4 to 7.6 sweet spot, and holding total alkalinity between 80 and 120 ppm so the system stays stable. Calcium hardness generally lands between 200 and 400 ppm depending on the surface, while cyanuric acid sits around 30 to 50 ppm in most outdoor pools, sometimes higher in salt systems. Combined chlorine, or chloramines, should ideally be zero—anything over 0.5 ppm is a sign the pool is starting to struggle.

What Happens When the Water Falls Out of Balance

When chlorine drops too low, the water is no longer protected. It starts dull, turns cloudy, and eventually gives way to algae while chloramines begin to build. On the flip side, excessive chlorine usually shows up as irritation—burning eyes, dry skin, and unnecessary wear on liners and equipment.

pH is where most problems begin. When it falls too low, the water becomes aggressive, leading to corrosion and that sharp, uncomfortable feel swimmers notice right away. When pH climbs too high, chlorine loses effectiveness, which opens the door to cloudy water, scaling, and the slow buildup of problems that don’t resolve on their own.

Total alkalinity acts as the buffer for all of this. If it’s too low, pH becomes unpredictable and difficult to control. If it’s too high, pH tends to drift upward constantly, making the pool harder to manage over time.

Calcium hardness affects the pool surface more than anything. Low calcium creates “hungry” water that pulls minerals out of plaster, while high calcium leads to scale buildup on tile, heaters, and salt cells—often accompanied by cloudy water that refuses to clear.

Cyanuric acid is one of the most misunderstood factors. Without enough of it, chlorine gets burned off by sunlight almost as quickly as it’s added. With too much, chlorine becomes far less effective, creating situations where test results show adequate levels, but algae still appears.

Chloramines tie it all together. When they show up, it’s a clear signal that chlorine isn’t finishing its job. That’s when you get the strong smell, the irritation, and the sense that the water just isn’t right.

The Right Way To Think About It

At the end of the day, most people who are managing a pool’s chemistry aren’t looking at these numbers in isolation. Chlorine is the worker, pH determines how effective that worker is, cyanuric acid protects it from the sun, and alkalinity keeps the entire system from swinging out of control.

When those elements are in line, the pool runs clean and predictable. When they’re not, every visit turns into a problem-solving exercise.