Does boiling water remove chlorine? If you’re concerned about chlorine in drinking water, and want clean water that’s safe for your family, you’re not alone. Many households today seek ways to remove chlorine from drinking water to improve taste, reduce chemical exposure, and support better health. Boiling is simple and well-known, but how much does it really help remove chlorine or other contaminants from your tap water?
The short answer: Boiling water does remove most free chlorine, but not all types of disinfectants, and you should consider other methods if your water contains more stable forms like chloramine. Some risks and limits exist, and better ways to remove contaminants may work faster and more reliably. This guide gives you real data, step-by-step advice, and modern solutions based on today’s best water science.
How Does Boiling Water Remove Chlorine?
Tap water can contain chlorine, added by water treatment plants to kill bacteria and viruses. While this improves safety, it can leave an unwanted taste and odor, leading many people to seek ways to remove chlorine from drinking water at home.
So, how does boiling help?
- Chlorine is a volatile gas. "Volatile" means it can change from a liquid to a gas at a temperature much lower than water boils.
- When you boil uncovered water, chlorine molecules are released into the air.
- Chlorine’s boiling point is –34°C—much lower than water’s 100°C. As soon as the water heats up, chlorine begins to evaporate.
- The process is called volatilization—as you boil water, it causes the chlorine to evaporate quickly.
This simple chlorine removal method explains why boiling water can remove chlorine, although it only works for free chlorine—not all disinfectants.
Step-By-Step: What Happens When You Boil Water With Chlorine:
- Heating: As the water heats up, chlorine starts to convert into a gas before the water boils.
- Boiling: Rolling boils help the chlorine escape even faster.
- Evaporation: The gas rises and leaves the pot, lowering chlorine levels in your water.
It is important to keep the pot uncovered so the chlorine can leave. Using a lid will trap the gas and slow down removal.
How Effective is Boiling at Removing Chlorine? (With Real Data)
Will boiling water remove chlorine completely? How long do you have to boil water to remove chlorine? Scientific studies help answer these.
- Boiling water does reduce free chlorine levels dramatically.
- Boiling for 15–20 minutes can often lower chlorine by 50–80% or more.
- The starting chlorine level, the water amount, and if you keep the pot uncovered all matter.
Data Table: Chlorine Removal by Boiling Time
| Boil Time | Avg. Chlorine Reduction |
| 5 minutes | ~20% |
| 10 minutes | ~35% |
| 15–20 minutes | 50–80%+ |
Key Tips:
- Uncovered pots are best. Keeping water uncovered lets chlorine molecules escape more quickly.
- Boil larger amounts longer. If you are boiling a lot of water, 20+ minutes may be best.
- Higher starting chlorine? Longer boiling works better if your tap has high chlorine.
Real Lab Study Example: One study found boiling tap water reduced free chlorine from about 0.5 ppm to 0.24 ppm after 15 minutes—a reduction of over 50%.
Factors That Affect Boiling Effectiveness
How fast does boiling water remove chlorine? it’s worth noting that factors like altitude can influence how fast chlorine escapes：
- Altitude: At higher altitudes, water boils at lower temperatures, which can slow chlorine evaporation.
- Pot size and depth: Shallow, wide pans (more surface area) work faster.
- Initial chlorine concentration: the more chlorine present, the longer it takes.
Does boiling water take out chlorine completely? No, small traces can remain, especially if boiling time is short or your water has a lot of added chlorine. For most households, boiling reduces chlorine to much lower levels but does not always make it undetectable.
Does Boiling Water Remove Chloramine? Key Differences Explained
Many cities now add chloramine (a mix of chlorine and ammonia) to their water because it lasts longer than regular chlorine. This important difference affects how you remove disinfectants from tap water.
What Is Chloramine?
Chloramine, a combination of chlorine and ammonia, is resistant to boiling. According to the EPA, chloramine is significantly more stable than free chlorine and does not evaporate during boiling. Removing chloramine requires special filtration, such as catalytic carbon or reverse osmosis systems.
| Chemical | Removed by Boiling? | Notes |
| Free Chlorine | Yes | Boiling 15–20 min is effective |
| Chloramine | No | Highly stable—resists boiling: needs special filters |
Chloramine:
- Will not be removed by regular boiling.
- Needs a special water filter (activated carbon filters made for chloramine) or a reverse osmosis filtration system.
Want to know which disinfectant your city uses?
- Check your local water supplier’s website for water quality reports.
- You can also use water test strips at home.
Alternatives: Better Ways to Remove Chlorine and Chloramine
While boiling works for free chlorine, it is not always the fastest or most efficient method, especially for frequent or large-scale needs. There are other ways that can remove both chlorine and chloramine from your drinking water.
Activated Carbon Filters
- Good at removing chlorine.
- Remove chloramine if labeled for it (not all carbon filters will).
Reverse Osmosis (RO) Filtration
- Removes chlorine, chloramine, plus many other contaminants.
- A full RO system often includes advanced carbon stages.
Letting Water Sit (Off-Gassing)
- Only works for chlorine, not chloramine.
- Takes 24 hours or more and is slower than boiling.
Comparison Table: Ways to Remove Chlorine & Chloramine
| Method | Removes Free Chlorine | Removes Chloramine | Practicality |
| Boiling | Yes | No | Needs time, energy |
| RO Filter | Yes | Yes | Fast, effective, reliable |
| Carbon Filter | Yes* | Yes** | Quick, easy (if correct filter) |
| Off-Gassing | Partial | No | Slow (24+ hours), incomplete |
For chloramine, make sure your filter is certified for chloramine removal.
Choosing the Right Method: Boiling, Filtration, or Both?
When trying to remove chlorine from your water, it’s essential to match the treatment method to the specific disinfectant used in your municipal water. Depending on whether your tap contains free chlorine, chloramine, or an unknown mixture, your strategy will vary.
If your public water supply uses free chlorine, the process is straightforward. You can simply boil the water for 15–20 minutes in an uncovered pot. This method works because chlorine is volatile—it evaporates as the temperature rises. Boiling is a quick and low-cost way to reduce the level of chlorine, especially if you're dealing with a typical amount of chlorine found in most water supplies.
However, if your water system uses chloramine—a more stable compound made of chlorine and ammonia—boiling won’t work. Chloramine does not evaporate like chlorine, so even after boiling, it may still be present in your drinking water. In this case, you'll need a reverse osmosis (RO) system or a certified carbon filter designed specifically to remove chloramine. These systems can effectively remove chlorine and chloramine, along with other contaminants, giving you much cleaner water.
If you're unsure whether your tap water has chlorine or chloramine, or if your water supplier doesn’t provide clear data, the safest route is to use a reverse osmosis filter. A reverse osmosis water filtration system is a powerful tool to remove chlorine from your drinking water and eliminate chloramine, PFAS, lead, and more. It’s a highly effective way to remove chlorine, delivering chlorine-free water for safer everyday use. If you want to remove stubborn contaminants, RO is often the best choice. It’s the best answer for anyone asking how to get rid of chlorine in tap water when the source is uncertain.
Some people try to let the water sit in an open container for 24 hours to neutralize chlorine naturally. This can work to some extent for free chlorine, but it's far slower than boiling and doesn’t touch chloramine.
In short:
Use boiling for free chlorine when you want a quick fix.
Use an RO system or chloramine-rated filter for long-term, reliable purification.
If your water’s disinfectant is mixed or unknown, choose RO to remove chlorine from water effectively and safely.
Summary Table: When to Use Boiling, Filtration, or Both
| Your Water Contains | Best Removal Method | Effectiveness | Practical Note |
| Free Chlorine | Boiling (15–20 min) | High | Quick, simple—no extra tools needed |
| Chloramine | RO system or Certified Carbon Filter | High | Boiling does NOT work for chloramine |
| Mixed/Unknown | Reverse Osmosis (RO) Filter | High | Removes both chlorine & chloramine + many other contaminants |
Safety Concerns, Myths, and What Boiling Doesn’t Remove
Many believe boiling tap water makes it "pure," but that's not always right.
Debunking the Myths:
Boiling increases some risks: While boiling removes free chlorine, it cannot remove all disinfection byproducts (like chloroform). Heated water can even cause some of these byproducts to get into the air, which you might breathe in. WHO warns that some chlorine byproducts—like chloroform—may increase cancer risk when ingested or inhaled at high levels over long periods. These disinfection byproducts can be released more into the air during boiling, especially in unventilated areas.
Boiling will not remove:
- Heavy metals (like lead or arsenic)
- PFAS ("forever chemicals")
- Nitrates, pesticides, pharmaceuticals, or hard minerals
- Microplastics
- Chloramine remains in the water after boiling.
Taste and Odor: Boiling can decrease the chlorine taste and odor. If you still notice an odor or strange taste after boiling, your tap water might contain chloramine or other substances.
At-Home Testing: Check Your Water After Boiling
Wonder if you’ve really removed most chlorine? You can check chlorine levels with test strips found online or in hardware stores.
How to Check Chlorine After Boiling:
- Collect some boiled, cooled water in a glass.
- Dip the chlorine test strip in for the recommended time (usually a few seconds).
- Match the color on the strip to the chart in the test kit.
- Compare your results with your local tap water’s reported levels.
For more detailed results—including chloramine, metals, and other chemicals—you can use a certified lab test.
Expert Insights
"Boiling water rapidly reduces free chlorine, but with the growing use of chloramine as a disinfectant, relying only on boiling is often not enough. Always check your water quality report and use a tested filtration method when necessary," says a water quality scientist.
Checklist: How To Remove Chlorine From Tap Water
Check your water’s disinfectant (local water report or test kit).
Free Chlorine?
- Boil for 15–20 minutes, uncovered
- Or let sit uncovered for 24 hours
Chloramine?
- Use a certified carbon filter made for chloramine
- Or install a reverse osmosis filtration system
Both or Unknown?
- Use a reverse osmosis filter for full protection
Test your water after treatment:
- Use a chlorine test strip and match color
- If unsure, send water for lab testing to
Key Takeaways
- Boiling water removes most free chlorine but does not remove chloramine.
- For full-spectrum water safety (chlorine, chloramine, metals, PFAS, and more), use a reverse osmosis water filtration system that includes specialized carbon filters.
- Always match your purification method to the chemical disinfectant your water supplier uses—get this from your supplier’s water quality report or reliable at-home test kits.
- Boiling is a quick, simple method for lowering chlorine from drinking water when only chlorine is present but offers no protection for chloramine or other contaminants.
FAQs
1. How long do you have to boil water to remove chlorine?
To remove chlorine from tap water, you should boil the water in an uncovered pot over high heat for 15 to 20 minutes. Chlorine is very volatile and will begin to slowly escape into the air before the water comes to a full boil. Boiling for only 5 to 10 minutes does remove some of the chlorine, but it takes a long time to remove it completely. Boiling for 15 to 20 minutes will remove most of the chlorine, at least 80%. However, the exact results depend on practicalities such as the altitude of where you live, the size of the pot, and the amount of chlorine that would have been in the water. If you are not sure how much chlorine is left in the water after boiling, you can test it with a test strip before drinking. It is important to note that this method only works for free chlorine, and will not work if there are chloramines in the water, which are too stable and must be treated with special filtration methods.
2. Does boiled water get rid of chlorine?
To get rid of chlorine in water, boiling it does work, especially free chlorine. Water treatment facilities often add free chlorine to sanitize the water. However, chlorine is volatile and starts to evaporate before the water boils, and when the water boils, it runs off even faster. Remember to leave the lid on the pot when boiling for 15 to 20 minutes, most of the chlorine will run off, and if you're lucky you'll be able to get rid of 50% to 80% or more. Exactly how much can be removed depends on how much chlorine is in the water and whether the fire is enough to boil it. But don't think boiling water is 100% safe, if there is chloramine in the water, boiling is useless. Chloramines are more stable than free chlorine, so ordinary heating can't do anything about it. Really want to completely clean chlorine, but also rely on reverse osmosis water purifier or activated carbon filter these professional equipment. Therefore, boiling water to remove chlorine, emergency no problem, can make the water taste less heavy disinfectant water, but also can reduce exposure to chlorine. But if the pursuit of completely chlorine-free water, you have to use specialized filtration equipment.
3. How to remove chlorine from tap water naturally?
If you want to remove chlorine from your tap water without using chemical methods, there is a simple way to do it: get a clean cup or container, pour in water, and leave it open for 24 hours. Free chlorine in water is a volatile gas that slowly escapes into the air over time. If you move the container into the sunlight, the dechlorination will be even faster, as ultraviolet light accelerates the decomposition of chlorine. However, the disadvantage of this method is obvious: it only works on free chlorine and is completely ineffective on the chemically stable chloramines, which will still remain in the water. If you use treated water for watering flowers, changing the water in your fish tank, or even drinking it directly, you will still need to use a chemical dechlorinator or install an activated charcoal water filter to ensure safety. While open static dechlorination is natural and convenient, the drawbacks are obvious: it's slow and the results are inconsistent. If the chlorine content in the water is high, the dechlorination effect cannot be guaranteed at all. Therefore, if you have strict requirements on water quality, it is recommended to test with chlorine test paper before use to confirm that the chlorine content is up to standard before use.
4. How do you dechlorinate tap water quickly?
The most straightforward way to quickly remove chlorine from your home's tap water is to pour the water into a pot, uncovered, and bring it to a boil over high heat, then boil it for 15 to 20 minutes. Free chlorine has a low boiling point, so it begins to be released as soon as the water is heated and evaporates more quickly when it boils. This method can quickly reduce chlorine levels by treating water used for cooking, drinking and even brewing baby formula.
5. Does chlorine disappear when boiling?
Boiling is a common method of removing chlorine from tap water. Boil water with the lid open for 15 to 20 minutes and most of the chlorine will evaporate as it boils. Chlorine is volatile and has a low boiling point. Once water is heated, it begins to release the gas. Therefore, boiling naturally reduces the amount of chlorine in the water and lightens its odor. However, this method is not foolproof: if the chlorine level in the water is too high or the boiling time is insufficient, the chlorine will not be completely removed. What's more, it is only effective against free chlorine and not against chloramines.
6. Is boiled water safe for pets, aquariums, or plants?
Boiling water does effectively reduce free chlorine levels, but chloramines and other contaminants may remain in the water. These substances can be harmful to sensitive pets, aquarium organisms, or plants. As chloramines are particularly hardy and can remain in the water even after it has been boiled, it is unsafe to keep aquatic organisms like fish and shrimp in boiled water alone, as chloramines can be toxic to them. Also, some delicate plants may be vulnerable to chemical residues or disinfection by-products , which cannot be removed by boiling. Should you plan to use treated water for pets, aquariums or flowers, it's a good idea to check your local water quality report or have your home water tested. The safest thing to do is to use a specialized filtration system, such as an activated carbon filter that is certified to remove chloramines, or a reverse osmosis system. In addition, there are chemical dechlorinators on the market that are specially formulated for aquariums, which can quickly and safely neutralize harmful substances in the water.
7. Is it safe to breathe steam from boiling chlorinated water?
Be careful when boiling tap water, inhaling the steam produced by boiling is actually a safety hazard, especially in poorly ventilated places. Once the water is heated, the free chlorine will evaporate, and then the volatile disinfection by-products such as chloroform and trihalomethanes will follow into the air. Prolonged exposure to these substances in a closed kitchen or bathroom can cause respiratory irritation or long-term health problems. Although the concentration of these compounds is not usually high, you should be extra careful if you have asthma, chemical sensitivities, or a weakened immune system. It's not hard to minimize the risk: always ventilate the room when boiling water, turn on the exhaust fan if you have one, and never smell the steam directly above the pot. If you often rely on boiling tap water to get rid of chlorine, why not simply change the filtration system, so that you don't have to boil water for long periods of time every day, and you'll be less affected by the steam.
8. Is boiling water cheaper than using filters?
Always thought boiling water for dechlorination was both cost effective and convenient? In fact, there are a lot of hidden costs! Especially when you often have to deal with a lot of water, with a gas stove or electric kettle to boil water, 15 to 20 minutes to get rid of some of the chlorine, not only time-consuming, electricity and gas bills also followed by the dawdling rise, every day so boiled, the account of life can be really uneconomical to do the math. Then look at the water purifier, such as activated carbon filter or reverse osmosis system, although the beginning to spend money to buy equipment, but in the long run it is really save money. A few gallons of water can be filtered without having to keep a fire going, and it's much more efficient than boiling water. The key is that it gets rid of a lot more -- chloramines, heavy metals, PFAS, and other contaminants that boiling water can't get rid of, and it does it all.
References
- U.S. Environmental Protection Agency (EPA). (2024). *Chloramines in Drinking Water*. https://www.epa.gov/dwreginfo/chloramines-drinking-water
- World Health Organization (WHO). (2017). *Guidelines for Drinking-Water Quality, 4th Edition*. https://www.who.int/publications/i/item/9789241549950