How Long Can Water Sit in a Pool Without Chlorine?

Nothing is done to the water in the pool for a week or a half, and then the water quality usually degenerates. Although the pool water remains more or less fine for another week, it is still not very fresh. But, how long can water sit in a pool without chlorine before it turns green?

The water stays clear for 24 to 48 hours before it turns cloudy in a chlorine-free pool. The outside temperature also plays a significant role. From 95 °F, there is a greater risk that the pool will suddenly turn green if no pool pump is circulating the water.

In this article, I will talk about how long can water sit in a pool without chlorine. In addition, you will find suitable alternatives to chlorine in the text.

How Long can water sit in a pool without chlorine?

Maybe you want to go on a holiday vacation or visit your family for a few days and have no neighbor who will take care of your pool.

Then you ask yourself how long your pool water will stay clean without chlorine before it turns green.

In my experience, the pool water can stay around 3 to 6 days without chlorine before it gets cloudy.

But I have to mention that the filter pump was running shortly during this time with the help of a pump timer.

Without a running pool pump, I think the water will turn green in a shorter period because the pool pump helps to circulate the water and keep it from stagnating.

If you add some algaecide to the pool water, probably the water can sit in your pool one or two days longer.

The problem only arises when you run your pool without chemicals. In this case, the water can get dirty within 24 hours.

It is difficult to make a general statement as external factors play an essential role.

Accurate pool care is necessary, especially on hot days, to keep the water clean.

How Long Can Water Sit In A Kiddie Pool Without Chlorine?

The water should be changed like clockwork for most inflatable pools or plastic kiddie pools.

Assuming you are not adding chlorine to kill microscopic organisms in the kiddie pool. The pool water without chlorine can become cloudy in just 24 to 48 hours.

But let me tell you this.

I added one teacup of chlorine in a little Intex Pool. There was no filter pump running, and the pool water stayed clean for about three days before it got the greenish tint.

It was over 95 °F, and the water in the Intex pool would probably turn green within 24 hours without chlorine.

By using a little cartridge filter, the water will probably stay clean for one more day.

I recommend changing the water every three days as it is acceptable in such a small pool.

Tip: You can read my full Intex pool care Guide for free in the blog. Follow the link to read the guide.

What Happens If You Don’t Use Chlorine In Your Pool?

Many pool owners ask this question as pool water care is expensive.

But it is no secret that your pool will turn green if you don’t use chlorine or another disinfectant.

Bacteria, fungi, and various microbes can take over the pool water without chlorine.

You cannot see these tiny creatures, but they are there.

And, they will grow if you run pool water without chlorine for too long.

If you go on holiday, do not neglect pool maintenance because bacteria and other microorganisms invade pool water when chlorine is absent.

Ask a friend or neighbor to take care of your pool when you are away.

Make the pool care easier for them by leaving a pool maintenance plan. You can print out my instructions on pool cleaning to be on the safe side.

What Are The Alternatives Of Chlorine?

Chlorine is one of the most popular chemicals for water disinfection.

The principle of chlorine: Suppression of the enzymatic systems of pathogenic microorganisms.

But maybe you don’t want to add chlorine to your pool water. In this case, there are some alternatives to chlorine. See this alternative below.

Tip: I explained in my blog post how to clean a pool without chlorine. Click on the link to read the instructions.

Active Oxygen:

One of the most effective cleaning methods is water disinfection using active oxygen.

Principle of action: The chemical, interacting with water, decomposes and releases oxygen.

  • The chemical effectively fights various types of bacteria, fungi, and viruses.
  • Unlike chlorine-containing preparations, no by-products are released into the water.
  • Do not dry skin after visiting the pool.

According to the form of release, preparations based on active oxygen are in the form of granules and liquid.

And the best part is that active oxygen can be used in any pool since the drug cannot damage the bowl material.


The ozonation method speaks for itself: Purification takes place with the help of ozone, destroying bacteria, viruses, and fungi by oxidation.

Unlike chlorine and active oxygen, ozone helps to cope with a wide range of bacteria, including spore forms.

  • After ozonation, no side elements are formed in the water.
  • Ozonation does not change the chemical composition of the water.
  • It is impossible to overdose.
  • Ozone destroys harmful bacteria only in the water column, and they remain viable on the walls of the pool.

UV Lamps:

This method works on the principle of the effect of UV radiation on bacteria, disturbing them of their ability to divide.

  • This cleaning method is recognized as the most environmentally friendly.
  • Effectively fights dirt by breaking down organic particles.
  • Decomposes chloramines present in water.
  • Does not change the chemical composition of water and does not impart an unpleasant odor.
  • Completely safe for the health of bathers.

Among the disadvantages is the lack of prolonged action and the resistance of some types of bacteria to UV radiation.


This method is based on the release of silver and copper ions in the filtration system. Silver ions fight bacteria and viruses, while copper helps kill algal spores in the water.

In addition to fighting bacteria and algae, ionization prevents plaque build-up on the sides of the pool.


With the help of ultrasound, pathogens’ cell walls are deformed, and contaminating compounds are destroyed. This method effectively fights even heavy haze and dirt.

Is It Safe To Swim In A Pool Without Chlorine?

Okay, let’s assume that you read how dangerous chlorine is, and for now, you don’t want to add it to your pool anymore.

You could likely swim in a pool without chlorine with practically no significant medical problems.

But the truth is, swimming in a pool lacking disinfectants could make you sick.

You could likewise be in danger, assuming that you have an open sore or cut, so it’s eventually best to swim in a pool with chlorine and other appropriately adjusted synthetics.

The other fact is that, as described above, your pool gets dirty quickly.

Then you no longer wonder whether it is safe to swim in a pool without chlorine because nobody really wants to take a bath in the broth.

Do you have further questions about pool water and chlorine?

Contact me on Twitter at @contactswimfool. I am happy to help you.

Happy swimming!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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