Does Boiling Water Remove Chlorine?

You’ve probably heard that chlorine in drinking water is harmful to your health and are wondering if boiling water removes it. I was curious as well, so I read all the available literature about chlorine removal (at least I tried to). I used what I learned to help readers concerned about chlorine removal know their options.

What Is Chlorine and Why Is It Used in Drinking Water?

Chlorine, or “free chlorine,” is a common chemical disinfectant added to tap water for the purpose of killing bacteria and other contaminants. This process is referred to as water chlorination. It kills bacteria, viruses, and contaminants that cause illness and disease. For more information about water treatment, read my article on the subject. 

Chloramine, a combination of chlorine and ammonia, is also widely used in public and private water systems. However, some people prefer to remove chloramine and chlorine from their water. 

Is Chlorine in Your Water Harmful?

The United States Environmental Protection Agency (EPA) limits the amount of free chlorine in drinking water to levels that are safe for human consumption (up to 4 mg/L or 4 ppm). At this level or lower, the chlorine used to disinfect water is unlikely to cause long-term health effects.

On the other hand, excessive chlorine intake over a long period can cause health problems. 

Adverse Effects of Chlorine

Drinking over-chlorinated tap water has been linked to several health issues. Some of these effects are caused by trihalomethanes. Trihalomethanes (THMs), such as chloroform, are formed when chlorine reacts with tiny organic particles in water.

These byproducts have been linked to negative health effects with varying degrees of severity.

Unpleasant taste and smell

Even if the chlorine and chloramine levels in your drinking water are safe, you may notice an unpleasant taste or odor. If your water tastes or smells odd, you’re less likely to drink it, and drinking too little water can lead to dehydration. 

When your water tastes bad, you and your family are more likely to consume less healthy beverages, like soda, or to buy bottled water, both of which have their own set of problems.

Breathing problems

One of the direct side effects of over-chlorination in your water is respiratory problems. Some studies have shed light on the link between excessive chlorine consumption and asthma and other respiratory problems. 

Swimming in chlorinated water has also been linked to symptoms of “bronchial hyperreactivity, asthma, and rhinitis, particularly in children, elite swimmers, and indoor pool employees” in a study published in the Polish journal Annals of Agricultural and Environmental Medicine.

Skin diseases

Doctors are concerned that chlorine not only kills harmful bacteria, but also kills the beneficial bacteria that keep your skin healthy. As such, continuous chlorine exposure can cause dry skin or acne. According to the Minnesota Department of Health, some people may experience skin irritation if they are extremely sensitive to chlorine.

Cancers

According to Johns Hopkins University researchers, who published their findings in the peer-reviewed journal Environmental Sciences & Technology, when chlorine is added to tap water, new toxic and carcinogenic byproducts are produced. Although chlorination is not directly linked to cancer, the presence of a newly discovered byproduct of chlorination, the toxic compound and known carcinogen BDA (2-butene-1,4-dial), may be harmful to health, according to the researchers.

Pregnancy complications

THMs, which are found in chlorinated water, can be harmful to pregnant women. Children may be born with birth defects, such as ventricular septal defects, immature brain development, or cleft palates, as reported in a number of studies on this issue. 

How Do You Check Chlorine Levels in Your Water?

Now you must be wondering about the chlorine levels in your own water. If your tap water smells like bleach, it may be over-chlorinated, but you can check your water’s chlorine levels using multiple official methods as well. 

Professional laboratory test

You can have your water sample professionally tested by labs authorized by the EPA or your state. The majority of labs send chlorine test kits to your home. Simply fill the sample bottle with your drinking water and return the package (this is the most convenient method to check the amount of chlorine).

At-home methods

If you want a cost-effective method to test chlorine levels in the comfort of your home in just a few minutes, then you can try at-home chlorine testing kits. A chemical named DPD (diethyl-p-phenylenediamine) is used to check chlorine in your water sample. It comes in multiple varieties, e.g. tablets, drops, and strips. You can buy any of these at your convenience to check chlorine. 

A device called a colorimeter also measures the amount of chlorine in water by using light beams to measure the concentration of chlorine in different samples by the difference in colored light. It is also available for purchase to check free chlorine at home. 

For more information about at-home methods for checking your water’s chlorine levels, read my article “How to Remove Chlorine from Water.”

Does Boiling Water Remove Chlorine?

Yes, boiling chlorinated water does remove chlorine. 

Chlorine is highly volatile in water. Due to this volatile nature, it will eventually escape from the water. Raising the temperature increases the amount of chlorine that can evaporate in a given amount of time, so boiling it for 15–20 minutes should remove a significant amount of the chlorine.


The effectiveness of boiling is affected by the surface area of the water. As a result, when you boil a large pot of water, chlorine is removed faster than when you boil water in a narrow column. 

For large amounts of water, though, boiling is not a viable dechlorination method. Unless you boil water for a long time (20 minutes or longer), boiling does not remove a significant amount of chlorine and chloramine.

How Else Can You Remove Chlorine From Water?

Evaporation

One of the simplest methods for removing chlorine is to simply let it evaporate over time or sit overnight. To do so, simply place your tap water in a large open container and allow the chlorine to evaporate within several hours.

Several factors influence the effectiveness of chlorine evaporation, including the temperature of the water, the size of the container, the acidity, or pH, of the water, and the level of chlorine to begin with. That’s why dechlorinating tap water by evaporation regularly might not be the best plan. 

Reverse osmosis system

A reverse osmosis filter system is one of the most effective methods for removing chlorine. Reverse osmosis filters are installed directly to a tap water source. This means that before leaving the faucet, the water passes through a thin membrane. The membrane captures contaminants, such as chlorine, before the machine dispenses water into your glass, removing nearly all impurities.

Filtering accomplishes everything that boiling does and more. It can remove impurities such as traces of limescale, heavy metals, chlorine, and other chemicals, and eliminate odors. 

It’s not a perfect method to remove chlorine, though. One disadvantage of this method is that some reverse osmosis filters remove all minerals, including beneficial minerals. After filtering out all the impurities, a good reverse osmosis system will add in beneficial minerals, leaving the water cleaner and healthier than before.

Activated charcoal filter

Activated charcoal filters (or activated carbon filters, the terms are interchangeable) effectively remove free chlorine and other unpleasant tastes and odors. High-quality activated carbon filters can remove up to 95% of chlorine. A charcoal filter removes chlorine through a chemical reaction. 

Activated catalytic (more reactive) carbon chemically alters the chlorine molecules, resulting in chloride formation. Those chloride particles are trapped in the tiny pore spaces of activated carbon, allowing dechlorinated water to pass through.

Activated carbon filters are also used in various water filtration systems, such as distillation units, filter pitchers, RO systems, and gravity-based water filters to remove chlorine from water.

For a better experience, use granular activated carbon (GAC) filters or carbon block filters.

Distillation

Distillation is a more advanced method than evaporation and filtration systems. It involves heating water to its boiling point and then cooling it to recondense the steam. This produces pure water as a result. 

“Distillation can . . . remove many organic compounds, heavy metals (such as lead), chlorine, chloramines, and radionuclides,” according to experts.

Distillation is a better way to purify water than boiling because it removes all possible contaminants, leaving pure water, whereas boiling the water may remove some contaminants, but not all of them. Distillation performs better than water filters, as well, in terms of removing contaminants. 

Distillation units are frequently installed using point-of-use (POU) systems. They are usually installed at the kitchen sink for drinking and cooking with distilled water. 

Conclusion

Now you have the answer to your question, Does boiling remove chlorine? But while boiling water may remove chlorine and chloramine, and kill bacteria, I would not recommend relying on it as the sole method of removing chlorine from your drinking water. It might be best for dechlorinating a small quantity of drinking water.

Other water purification methods, such as evaporation (for small-scale use), water filters (reverse osmosis or activated charcoal), and distillers, may be more convenient for regular home use than boiling. 

If you’re concerned about the possible effects of chlorinated water, you might want to have your drinking water regularly tested and consider employing one of these methods to remove chlorine from water.

You’ve probably heard that chlorine in drinking water is harmful to your health and are wondering if boiling water removes it. I was curious as well, so I read all the available literature about chlorine removal (at least I tried to). I used what I learned to help readers concerned about chlorine removal know their options.

What Is Chlorine and Why Is It Used in Drinking Water?

Chlorine, or “free chlorine,” is a common chemical disinfectant added to tap water for the purpose of killing bacteria and other contaminants. This process is referred to as water chlorination. It kills bacteria, viruses, and contaminants that cause illness and disease. For more information about water treatment, read my article on the subject. 

Chloramine, a combination of chlorine and ammonia, is also widely used in public and private water systems. However, some people prefer to remove chloramine and chlorine from their water. 

Is Chlorine in Your Water Harmful?

The United States Environmental Protection Agency (EPA) limits the amount of free chlorine in drinking water to levels that are safe for human consumption (up to 4 mg/L or 4 ppm). At this level or lower, the chlorine used to disinfect water is unlikely to cause long-term health effects.

On the other hand, excessive chlorine intake over a long period can cause health problems. 

Adverse Effects of Chlorine

Drinking over-chlorinated tap water has been linked to several health issues. Some of these effects are caused by trihalomethanes. Trihalomethanes (THMs), such as chloroform, are formed when chlorine reacts with tiny organic particles in water.

These byproducts have been linked to negative health effects with varying degrees of severity.

Unpleasant taste and smell

Even if the chlorine and chloramine levels in your drinking water are safe, you may notice an unpleasant taste or odor. If your water tastes or smells odd, you’re less likely to drink it, and drinking too little water can lead to dehydration. 

When your water tastes bad, you and your family are more likely to consume less healthy beverages, like soda, or to buy bottled water, both of which have their own set of problems.

Breathing problems

One of the direct side effects of over-chlorination in your water is respiratory problems. Some studies have shed light on the link between excessive chlorine consumption and asthma and other respiratory problems. 

Swimming in chlorinated water has also been linked to symptoms of “bronchial hyperreactivity, asthma, and rhinitis, particularly in children, elite swimmers, and indoor pool employees” in a study published in the Polish journal Annals of Agricultural and Environmental Medicine.

Skin diseases

Doctors are concerned that chlorine not only kills harmful bacteria, but also kills the beneficial bacteria that keep your skin healthy. As such, continuous chlorine exposure can cause dry skin or acne. According to the Minnesota Department of Health, some people may experience skin irritation if they are extremely sensitive to chlorine.

Cancers

According to Johns Hopkins University researchers, who published their findings in the peer-reviewed journal Environmental Sciences & Technology, when chlorine is added to tap water, new toxic and carcinogenic byproducts are produced. Although chlorination is not directly linked to cancer, the presence of a newly discovered byproduct of chlorination, the toxic compound and known carcinogen BDA (2-butene-1,4-dial), may be harmful to health, according to the researchers.

Pregnancy complications

THMs, which are found in chlorinated water, can be harmful to pregnant women. Children may be born with birth defects, such as ventricular septal defects, immature brain development, or cleft palates, as reported in a number of studies on this issue. 

How Do You Check Chlorine Levels in Your Water?

Now you must be wondering about the chlorine levels in your own water. If your tap water smells like bleach, it may be over-chlorinated, but you can check your water’s chlorine levels using multiple official methods as well. 

Professional laboratory test

You can have your water sample professionally tested by labs authorized by the EPA or your state. The majority of labs send chlorine test kits to your home. Simply fill the sample bottle with your drinking water and return the package (this is the most convenient method to check the amount of chlorine).

At-home methods

If you want a cost-effective method to test chlorine levels in the comfort of your home in just a few minutes, then you can try at-home chlorine testing kits. A chemical named DPD (diethyl-p-phenylenediamine) is used to check chlorine in your water sample. It comes in multiple varieties, e.g. tablets, drops, and strips. You can buy any of these at your convenience to check chlorine. 

A device called a colorimeter also measures the amount of chlorine in water by using light beams to measure the concentration of chlorine in different samples by the difference in colored light. It is also available for purchase to check free chlorine at home. 

For more information about at-home methods for checking your water’s chlorine levels, read my article “How to Remove Chlorine from Water.”

Does Boiling Water Remove Chlorine?

Yes, boiling chlorinated water does remove chlorine. 

Chlorine is highly volatile in water. Due to this volatile nature, it will eventually escape from the water. Raising the temperature increases the amount of chlorine that can evaporate in a given amount of time, so boiling it for 15–20 minutes should remove a significant amount of the chlorine.


The effectiveness of boiling is affected by the surface area of the water. As a result, when you boil a large pot of water, chlorine is removed faster than when you boil water in a narrow column. 

For large amounts of water, though, boiling is not a viable dechlorination method. Unless you boil water for a long time (20 minutes or longer), boiling does not remove a significant amount of chlorine and chloramine.

How Else Can You Remove Chlorine From Water?

Evaporation

One of the simplest methods for removing chlorine is to simply let it evaporate over time or sit overnight. To do so, simply place your tap water in a large open container and allow the chlorine to evaporate within several hours.

Several factors influence the effectiveness of chlorine evaporation, including the temperature of the water, the size of the container, the acidity, or pH, of the water, and the level of chlorine to begin with. That’s why dechlorinating tap water by evaporation regularly might not be the best plan. 

Reverse osmosis system

A reverse osmosis filter system is one of the most effective methods for removing chlorine. Reverse osmosis filters are installed directly to a tap water source. This means that before leaving the faucet, the water passes through a thin membrane. The membrane captures contaminants, such as chlorine, before the machine dispenses water into your glass, removing nearly all impurities.

Filtering accomplishes everything that boiling does and more. It can remove impurities such as traces of limescale, heavy metals, chlorine, and other chemicals, and eliminate odors. 

It’s not a perfect method to remove chlorine, though. One disadvantage of this method is that some reverse osmosis filters remove all minerals, including beneficial minerals. After filtering out all the impurities, a good reverse osmosis system will add in beneficial minerals, leaving the water cleaner and healthier than before.

Activated charcoal filter

Activated charcoal filters (or activated carbon filters, the terms are interchangeable) effectively remove free chlorine and other unpleasant tastes and odors. High-quality activated carbon filters can remove up to 95% of chlorine. A charcoal filter removes chlorine through a chemical reaction. 

Activated catalytic (more reactive) carbon chemically alters the chlorine molecules, resulting in chloride formation. Those chloride particles are trapped in the tiny pore spaces of activated carbon, allowing dechlorinated water to pass through.

Activated carbon filters are also used in various water filtration systems, such as distillation units, filter pitchers, RO systems, and gravity-based water filters to remove chlorine from water.

For a better experience, use granular activated carbon (GAC) filters or carbon block filters.

Distillation

Distillation is a more advanced method than evaporation and filtration systems. It involves heating water to its boiling point and then cooling it to recondense the steam. This produces pure water as a result. 

“Distillation can . . . remove many organic compounds, heavy metals (such as lead), chlorine, chloramines, and radionuclides,” according to experts.

Distillation is a better way to purify water than boiling because it removes all possible contaminants, leaving pure water, whereas boiling the water may remove some contaminants, but not all of them. Distillation performs better than water filters, as well, in terms of removing contaminants. 

Distillation units are frequently installed using point-of-use (POU) systems. They are usually installed at the kitchen sink for drinking and cooking with distilled water. 

Conclusion

Now you have the answer to your question, Does boiling remove chlorine? But while boiling water may remove chlorine and chloramine, and kill bacteria, I would not recommend relying on it as the sole method of removing chlorine from your drinking water. It might be best for dechlorinating a small quantity of drinking water.

Other water purification methods, such as evaporation (for small-scale use), water filters (reverse osmosis or activated charcoal), and distillers, may be more convenient for regular home use than boiling. 

If you’re concerned about the possible effects of chlorinated water, you might want to have your drinking water regularly tested and consider employing one of these methods to remove chlorine from water.