Is It Safe to Swim in a Pool Without Chlorine?

Is It Safe to Swim in a Pool Without Chlorine

Chlorine is the most popular water sanitizing chemical that makes swimming pools safe to swim in, but also causes some unfortunate side effects like irritated eyes, adverse effects to your respiratory system, dry skin, and bleached hair.

Many pool owners also dislike the chlorine smell and hate having to closely monitor the chlorine levels, as well as balancing the pH and alkalinity. So the question is: what if you just didn’t bother with chlorine at all? Is it safe to swim in a pool without chlorine?

Even if you’re adding fresh water to the pool and draining it after each use (a highly wasteful and costly thing to do), it still wouldn’t be safe because pathogens can be introduced into the water and spread that very session. You can try some chlorine substitutes, however they have their own downsides as well. If you want a completely chemical-free pool, unfortunately it would not be sanitary.

In this article, we’ll discuss the repercussions of not adding chlorine into the pool, what kind of chlorine substitutes there are and how they work, and if you can safely swim in a chemical-free pool.

What does chlorine do?

Before we discuss what it’s like swimming in a pool with little or no chlorine, it would benefit you to know exactly what chlorine does, and why it has become a ubiquitous chemical found in nearly all swimming pools.

There are four main things chlorine does:

  1. It kills bacteria, sanitizing the pool.
  2. It kills algae and prevents its growth.
  3. It oxidizes water, improving its clarity and quality.
  4. It maintains water at this stable water quality.

There are other chemicals that can provide some of these benefits, but few chemicals can provide all of these benefits simultaneously. Thus, you can reduce the amount of chemicals needed to sanitize your pool at a reliable consistency.

There are, of course, downsides to chlorine. It is well-known that chlorine contains the active agent used in bleach, and so it causes similar side effects when you are exposed to it. In other words, irritation of the eyes, mouth, lungs, skin, and hair is common. It can also damage your swimsuit or any other clothing worn in the pool.

Despite these downsides, they are relatively minor in the grand scheme of things, and the positives far outweigh the negatives. Thus, they are a necessary evil that many people have simply accepted.

You can protect yourself by wearing goggles, applying conditioner on your hair, and applying moisturizer on your skin and hair afterwards to mitigate the negative effects.

Since you are reading this article, you likely want to know if there are any alternatives to chlorine precisely because you don’t want to deal with these side effects any longer. Let’s discuss what happens if you simply decide to forgo adding chlorine in the pool.

What happens if you don’t add chlorine to the pool?

Since we covered what chlorine does for your pool, its absence will result in the problems that chlorine solves returning again.

Untreated water that is stagnant is host to a plethora of algae and bacteria that can cause infections and disease. The water clarity you were so used to will be quickly lost as the pool turns yellowish green as algae begins to grow.

If you thought chlorine had a bad smell, wait until you get a whiff of stagnant water. To be clear, it is basically indistinguishable from sewage.

You might think that this problem could be solved by just adding in fresh water each time you take a swim and then drain the pool completely before it starts to grow algae or stink.

However, this is a huge waste of water and your water bills would be astronomical. Plus, if multiple people are sharing the pool, pathogens and bacteria can potentially be spread in that very first swimming session. Imagine someone peeing in the pool with no chlorine around to neutralize the bacteria.

I think you would quickly realize that the cost of adding a small amount of chlorine is minimal for how many benefits you reap, and that any potential downsides are small problems that can be dealt with.

Alternatives to chlorine

So, just suddenly taking chlorine out of the equation is a bad idea. But what about substitute chemicals that can do similar things to chlorine? Perhaps there is an alternative that has fewer side effects.


The closest chemical to replacing chlorine is bromine. It is ideal if you have an allergy to chlorine, however its other downsides are similar to chlorine because it is part of the same halogen group as chlorine.

Bromine is most commonly used in hot tubs where it does a good job of working as a sanitizer, though it’s not as effective as chlorine.

Some homeowners prefer the hybrid form called BCDMH tablets, which contains 27% chlorine and 66% bromine to get the job done. The problem is that, once again, you are exposed to chlorine which we want to avoid.

Bromine is more stable at higher temperatures, which is why it is used in hot tubs or spas. It also tends to irritate the mucus membranes less than chlorine.

However, some downsides are that it has an odor and that it takes longer to oxidize water, so the water can remain a dull green color.

Saltwater system

Even though chlorine swimming pools are more popular, saltwater pools are starting to catch on in popularity. Many pool owners prefer having a salt system because it requires less chemicals and maintenance, is affordable in the long run, and is gentler on the skin, eyes, and hair.

How salt systems work is that there is a salt chlorine generator that can convert salt into chlorine. The system measures how much water is in your pool and then the generator will continuously convert some of the salt in the water into just enough chlorine to keep the pool sanitized.

Now, two questions you probably have are: isn’t swimming in saltwater really irritating? And, doesn’t this solution use chlorine, which is what we are trying to avoid?

First, the amount of salt required in a saltwater pool is approximately ten times less salt than the concentration of salt found in the ocean. Second, the amount of chlorine generated is also approximately ten times less than the amount of chlorine added into a chlorine pool.

Unless you are allergic to chlorine, all the other side effects of chlorine are basically not an issue anymore since the concentration of chlorine is so low in a saltwater pool.

A salt system gives you control over how much chlorine you want the generator to convert, as well as a monitor to regulate water flow, pump speed, and system potency levels.

With a saltwater pool, you save money and effort from not needing to buy chemicals since the generator will add chlorine for you. Ultimately, it requires less maintenance and largely avoids the downsides of chlorine.

The downside is that should the generator break, you need to call in an expert. Also, the initial cost of converting a chlorine pool to saltwater is costly, but may save you money in the long-term.


Another alternative to chlorine, though it is not widely known, is Baquacil. It works as an oxidizer and also isn’t quite as effective as chlorine, so pool industry experts debate on whether it is a worthy substitute to chlorine.

Baquacil can sometimes form an unsightly white mold in the water over time. It can keep water clean and clear for the first year of use, but eventually fails to maintain the water quality to a high standard.


An ozonator is a machine that connects to the filtration line and infuses ozone gas inside the pool. Ozone gas reacts with the impurities present in water, sanitizing it.

There are two types of ozone generators: corona and UV light discharge. For the UV light system, reduced-pressure vapor lamps are installed on the water-out line which creates ozone that eliminates pathogens floating in the water.

Corona discharge systems utilize an electrical arc to generate ozone. It also kills the pathogens within the filtration mechanism.

Using these generators can decrease the amount of chlorine needed to sanitize the pool by 90%, but you’ll still need some to achieve optimal results. However, these generators are most effective in a dry atmosphere, and are less effective in humid regions.


A pool ionizer uses a low-voltage direct current to disburse copper and silver metals into the pool. The positive charge attracts algae, bacteria, germs, and the larger compounds out of the pool from the filtration system.

Ionizers do not irritate the eyes or nose because it uses significantly less chlorine, but it still relies on chlorine. However, this does not help those who are allergic to chlorine.


Polyhexamethylene Biguanide, or PHMB for short, is a chemical that sanitizes your pool by entering the cell walls of the bacteria present and bursting them from the inside. Afterwards, it wraps the remains in a thick gel so that it can sink to the pool’s bottom, where the vacuum system can clean it up.

This solution is gentle on the hair, skin, and vinyl liners. It is also straightforward to keep the chemicals balanced.

However, it does not oxidize the water, so you will need to use hydrogen peroxide. You’ll also need to utilize different algaecides to keep algae away, and to thoroughly clean the filters every 3-4 weeks.

The bottom line

The technology to maintain a truly chlorine-free pool isn’t easy and is often more hassle than they’re worth. If not chlorine, then you would have to rely on another chemical for the job, and that chemical likely won’t even be as effective as chlorine.

Perhaps the question you’re asking isn’t whether it’s possible to swim in a completely chlorine-free pool, but rather how can you avoid the side effects of chlorine? To which the answer is that you can install a salt water system instead.

Saltwater pools still use chlorine to sanitize the water, but significantly less so that you won’t experience irritation on your eyes, skin, hair, or respiratory system. It also requires significantly less maintenance since the generator does the hard work of measuring and adding chlorine for you.

Most other systems such as ozone or UV generators are not completely free of chlorine, requiring small amounts of chlorine to help the water achieve an acceptable safety level.

The only truly chlorine-free option is PHMB. And no, simply forgoing chlorine but not replacing it with an alternative is not a real solution.