What can be a more relaxing way to spend your way other than swimming? Swimming not only cools and relaxes your body, but it is also one of the best forms of exercise. We all love pools that have clean water that is pathogen-free. After all, hygiene is always of utmost importance.

A certain amount of chlorine is used in swimming pools to make sure that the water meets the required quality standards. However, it might be a hassle to have to wonder if your chlorine levels are up to par constantly.

This is why we have summed up a detailed explanation of the why’s, the how’s, and the how to’s regarding chlorine usage in swimming pools.

With this article, you can understand the proper chlorine level as well as the relationship between chlorine and pH values. Additionally, we have included graphics that will let you know exactly how to lower or increase your chlorine levels.

Let’s dive right in!

Table of Contents

Why Does Maintaining Chlorine Level in Pools Matter?

Chlorine is undoubtedly one of the most commonly used substances for pool sanitization. However, before we get into understanding chlorine levels, we need to understand why maintaining it matters.

A chlorine level that is too high can cause damage to any pool equipment that you might have. This corrosive water can also bleach swimsuits or other clothing items. The swimmers may experience severe itchiness and discomfort. If consumed, this water can also cause chlorine poisoning. The symptoms of chlorine poisoning can include sudden nausea or vomiting, redness, dull chest pains, or itchy eyes.

A chlorine level that is too low can promote the growth of bacteria, algae as well as other harmful microorganisms. The increase in chlorine levels results in poor sanitation. Furthermore, it can lead to a pool that looks cloudy. This cloudiness is caused due to the pool’s reduced ability of oxidation. Increased chlorine level allows contaminants to accumulate and pollute the water.

Chlorine and pH

Chlorine levels and pH values are closely linked to each other. The pH scale measures how acidic or basic the water is within a range of 0 to 14. If the pH value is less than 7, it is acidic, whereas a value over 7 means that it has alkaline properties. A pH value of 7 means that the water is neutral.

The optimal pH value for your pool is about 7.4. This value is considered to be optimal because it matches the pH of the human eye as well as the mucous membranes. The ideal range is between 7.2 to 7.6. As chlorine reacts with the water, it tends to increase the pH of water, which is why a high pH correlates to a lower chlorine level.

Another reason they are so closely linked is that chlorine tends to lose its effectiveness in acidic water. This means that even if you have the right level of chlorine, high pH levels might make your pool dangerous to swim in. You can balance this by adding sodium bisulfate to reduce the pH or sodium carbonate to increase it.

pH valueConsequences
Less than 7Skin irritation
Eye irritation
Bleaching clothes
Corrosive effects on pipes
7.2- 7.6Ideal value
Greater than 8.0Low disinfection from microorganisms
Cloudy water

Proper Chlorine Level for your Pool

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The recommended levels of chlorine for your pool is between 1 to 3 ppm (parts per million). This value can be affected by the number of people using the pool. Similarly, heavy debris or high algae growth can require you to increase the chlorine levels. Poor circulation, high pH, or heavy exposure to sunlight are other factors that might demand additional chlorine.

According to the guidelines from the health department, public pools need to meet a minimum of 1.0 ppm chlorine level. For residential pools, this requirement may be lowered if any supplemental sanitizers are being used.

A chlorine level of above five ppm is considered to be too high. At this value, you are likely to experience irritation in your skin and around your eyes.

What about the Requirements for Stabilized Swimming Pools?

Stabilized swimming pools refer to pools that have an added cyanuric acid in them. This addition is required because, without added cyanuric acid, chlorine is likely to be burned off quickly in the sun. Cyanuric acid, thus, acts as a shield and prevents it from evaporating quickly.

However, some studies have concluded that this acid might also reduce the effectiveness of chlorine. This is why stabilized swimming pools need a higher level of chlorine, i.e., between 2 to 3 ppm.

How to Test Chlorine Level?

You can purchase testing strips that will let you measure the pH value of your pool. These strips can indicate how acidic or basic your pool levels are. Additionally, there are liquid reagent test kits that function on more or less the same principle. However, you need to ensure that these kits have not been previously contaminated to avoid faulty results.

If you need a more accurate reading, then you should use a DPD test kit. This will allow you to measure your free chlorine as well as pH values. DPD is short for N, N Diethyl-1,4 Phenylenediamine Sulfate.

How Often Should We Test Chlorine Levels?

The chlorine level and pH values should be tested at least twice a day. This rate is applicable if the pools are being used on an average amount. For heavy usage pools, testing should be conducted much more frequently.

What about the Chloramine Level?

Chloramines are the combination of ammonia or nitrogen with a free chlorine molecule, which is why they are also known as combined chlorine. When this happens, the chlorine molecule loses its effectiveness.

However, this reaction is more or less inevitable. This means that you have to expect some degree of chloramines in your pool. A permissible level is up to 0.3 ppm. Even at this value, you will need to shock your pool or super chlorinate it to break the chloramine bonds. The super chlorination should be up to 10ppm for it to be effective enough.

You can check your chloramine levels using the DPD test kit or test strips as well. The formula to use is TC – FC = CC, where TC= Total Chlorine, FC= Free Chlorine, and CC = Combined Chlorine.

How to Reduce High Chlorine Level in your Pool?

High chlorine levels can have many negative impacts on the swimmers as well as the pool equipment. Here are some of the immediate steps you can take to bring this level down:

  • Turn off any automatic chlorine feeders.
  • Reassess if your chlorine feeder is the right size for your pool.
  • Allow the UV rays to decrease the chlorine level naturally by leaving the pool uncovered. This process might take a few days. You can perform regular tests to check if it is working.
  • Dilute the pool by adding more water. If there is no more room, you can drain some of the concentrated water and add more water to speed it up.
  • Switch to chemicals like sodium carbonate.

Tip: Always wear gloves when handling chlorine. Please do not use the pool until chlorine levels have reached their recommended value.


Chlorine is highly effective for sanitizing your pool. However, levels under one ppm or over five ppm can have negative consequences on your skin and health. Make sure that you check your chlorine levels and pH values frequently. If you have any confusion, you can refer to the chart linked above. Until then, happy swimming!

(Last Updated on June 11, 2020 by Sadrish Dabadi)

Nina Howell is a Rewenable Energy researcher and consultant based out of Houston, Texas Area. She earned her Master's Degree in Energy and Earth Resources from Austin Jackson School of Geosciences in 2010, and a Bachelor's Degree in Environmental Science from State University of New York College of Environmental Science and Forestry in 2008. Nina has been working in the energy sector since 2011. She worked as an Energy Supply Analyst from 2011 to 2017 in Bounce Energy and then as a Research and Energy Consultant at GE Renewable Energy from March 2017 to February 2020 . Nina is a mom of 2 beautiful children who are joy to her life. She strongly believes in eco-friendly living and is vocal about renewable energy, environmental issues, water crisis, and sustainable living.