It’s happened to us all: After a fun and long day of swimming, our eyes feel irritated and bloodshot. It’s been a long-standing belief that the chlorine in the pool is the cause. It is almost well-known that chlorine can cause red, itchy eyes. Is chlorine causing red and irritated eyes? Are we being duped into believing something we don’t believe all these years? We will explore the following in this article:

  • Red Itchy Eyes: A Scientific and Logical Exploration
  • The Swimming Pool: The Major Causes of Red and Itching Eyes

Itchy eyes, science, logic

Let’s begin by looking at this question from a logical perspective. All pools should be chlorinated for safety. If all US pools are chlorinated, why don’t swimmers who open their eyes underwater feel the scratchy, stinging sensation? This logic leads us to dig deeper into the topic. Science is the best place to dig deeper. The Centers for Disease Control say that chlorine is not responsible for eye irritation. According to the CDC, the culprit for the stinging sensation in the eyes is chloramines. Let’s find out more about chloramine and how it can irritate.

There are several major causes of red and itchy eyes in the swimming pool


When a contaminate (pee or poop) is introduced into the water, chloramines are created. Our sanitizer, chlorine, is used to kill or inactivate harmful pathogens. It combines with the contaminate and then goes to work, killing them off. The chlorine does its job, and the pathogen is eliminated. However, the chlorine “kills” itself. Chloramine is formed when the inactive contaminate bonds with chlorine. According to the CDC, this is what causes eye irritation.

CPO(r), Certified pool operators are taught to remove chloramines from water. It is easy. Assuming your pool operator is doing their job. If you have removed the chloramines, why is your eye still itching? After 24 years of experience with swimming pools, I can confidently say that chloramines do not cause most eye itching. Chloramines will not affect the eyes as long as the chlorine levels in the water are below.5ppm. What is causing my eyes to be red and itchy despite these low chloramine levels?

pH Balance

Even the most “reliable” sources can make it easy to misdiagnose the cause of itching eyes in the pool. Industry experts and scientists know that eye irritation is often caused by pH imbalance, not chloramines. The science is simple: A human tear has a pH level of around 7. It would follow that any substance (e.g., pool water) with a different pH will irritate. Eye irritation is caused by the pH imbalance in the pool water.

To ensure that chlorine kills pathogens as effectively as possible, pool managers should maintain pH between 7.2 to 7.8. Swimmers with sensitive eyes may feel discomfort and itching if the pH falls below these levels. It is almost a given that swimmers with more sensitive eyes will experience itching and dry eyes.

But is Chlorine Innocent?

We’ve seen that chlorine is 99.9% harmless and not responsible for itching, watery eyes, or red eyes. One last possibility is sensitivity, but it is very rare. Although this isn’t a serious condition, it can signify low-level contact dermatitis. Although this is rare, it can happen. However, if it does, it can be caused by chlorine if you have sensitivities. If you are not diagnosed with sensitivities, it is possible to assume that your burning and itching are due to another factor.

Get CPO(r), Certified Today to Learn More about Pools and Hot Tubs

As much as we would like them to be, maintaining pools and spas is not an easy task. To ensure the health and safety of our spas and pools, it is important to have a solid understanding of how everything works together. Many options are available to help you learn more about keeping your pool clean and your swimmers safe. CPO classes with Pool Training Academy are one of the options. CPO(r), or Certified Pool Operator, is one of the best methods to become an expert in pool management. This certification is required in many states to be able to operate a spa or pool commercially. Pool Training Academy is the number one provider of CPO(r), and our classes are designed to be engaging, fun, and relevant to your specific needs. Register here for the next class or take an online course to learn all you need to make your pool as great as possible.

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