Does Boiling Water Remove Chlorine and Chloramine?

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Natural Chlorine removal methods eventually become of interest to anyone who keeps aquarium fish or just dislikes the taste of chlorinated water.

You could remove Chlorine from tap water by boiling it, but will that be enough to completely drive it out?

What about its less volatile and more stable substitute – Chloramine?

Will such a treatment yield sufficient results?

Does boiling tap water remove Chlorine efficiently?

If you’re using water from the tap for your home aquarium then removing its Chlorine contents is absolutely essential for keeping your pet fish safe. Here’s what happens with water when being boiled and if that removes free Chlorine:

There’s an inverse relationship between your tap water’s temperature and how much gas it can withhold. Boiling chlorinated water will decrease its ability to hold gasses and force the free Chlorine out. Free Chlorine remains as dissolved gas in water at temperatures of above -29.2 °F (-34 °C).

water bubbles

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Boiling your city water is the fastest natural way to remove Chlorine from it. In that regard, it will make it safe for aquarium fish, and it will eliminate the unpleasant taste for drinking purposes.

Also, typically, boiled tap water is considered drinkable.

What about boiling out Chloramine from the water?

Chloramine is the chemical bond between Ammonia and Chlorine and is less volatile and reactive than the free Chlorine molecules.

These qualities enable dissolved Chloramine to stay a lot longer in tap water than Chlorine.

It is the main reason why most modern water facilities have switched to Chloramine for disinfection.

Here’s what happens when you try to boil Chloramine out of tap water:

Boiling speeds up the evaporation of Chloramine from tap water significantly, but it still remains a relatively slow process. You’ll need to boil 10 gallons of water for at least an hour to completely remove 1 mg/L (milligram per Liter) of Chloramine. Therefore it’s not feasible to try and boil Chloramine out of larger volumes of tap water.

It is rare for your city water to contain less than 2 mg/L of Chloramine.

In some cases it can hold up to 4 mg/L as per the Environmental Protection Agency’s regulation.

How long should you boil the water to completely clear it from Chlorine and Chloramine?

boil water

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Chloramine takes up to 17 times longer than Chlorine to completely gas off from water that’s being boiled.

However, Chlorine outgasses relatively fast under the same conditions.

I did some research on the exact time needed and wrote down my own measurements, which gave me these results.

Visit the link where I discuss evaporation speeds of Chlorine and Chloramine in detail.

I also provide a chart that can be used to calculate the needed time to boil your tap water, depending on the levels it contains.

In short, a concentration of 1 mg/L of Chlorine will take 3.7 minutes to evaporate from 10 gallons of boiling water.

The same amount of Chloramine will take a little over 60 minutes.

To check whether you’ve successfully removed chlorine and chloramine from your tap water you can test it.

There are both aquarium-grade water tests and at-home Chlorine test kits for this.

There’s no way to tell the Chlorine contents of water without a test kit.

Is boiled water safe to use in an aquarium?

Boiling in itself means to heat up the water enough to evaporate some compounds from it and kill most of the bacteria in it.

Both of these can be beneficial for fish tank water.

However, just boiling water does not necessarily make it a good addition to your aquarium.

Factors like whether the water is hard or soft, acidic or alkaline play a role in how it will affect your pet fish.

These depend on the individual requirements for water your fish may have.

If we’re talking strictly freshwater aquariums, then Guppies, platies, and Endler’s livebearers like hard water, whereas Gouramis and most nano tropical fish like soft water.

For this reason, I can’t state that just boiling water will instantly make it suitable or healthy for a fish tank.

What are some alternative ways to remove Chlorine from tap water?

There are many ways to purify tap water from Chlorine and Chloramine besides boiling. These alternative methods may not work as fast but some of them are more practical than boiling gallons of water.

Here’s are some other ways to remove Chlorine and Chloramine from water besides boiling:

  • Have a Reverse Osmosis / De-ionization water filtering system at home. Installing a Reverse Osmosis (RO) and De-Ionization (DI) system at home can help remove not only chlorine but all kinds of impurities from your tap water. There are systems for both drinkable water and aquarium purposes.
  • Run a source of UV light over the water. Ultraviolet light in any form makes Chlorine leave water naturally. Two ways to use UV light to purify tap water from Chlorine are leaving a bucket of the water in the sun for two days and getting a UV water sterilizer for aquarium purposes. UV sterilizers work the fastest from the two. If you’re getting one to dechlorinate water, use it in a separate bucket, and not your fish tank. No chlorinated water should enter a fish tank.
  • Run the water through dedicated carbon filters. You can get those separately but a typical RO/DI filter system has them included in the pack. There are activated carbon, standard carbon and activated charcoal filters – all of those would work for removing Chlorine from water.
  • Distill the water. Distillation is a way to remove pretty much anything from water and completely purify it. However, it’s an expensive and lengthy process, making it difficult to do at home. Also, if you end up using distilled water in your aquarium it should be remineralized with the vital minerals a fish would need.

My Conclusion

Removing Chlorine and Chloramine from water through boiling is not only possible but in some cases, the most effective way to do so.

Leave me a comment below if you have more questions or want to share your experience with my readers.

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Momchil Boyanov is the Founder and now Senior Editor of AquAnswers. He has over 13+ years of experience in keeping home aquariums as well as providing professional aquarium services. Momchil has had his fair share of adventures in aquarium care. He has made MANY mistakes throughout his fishkeeping journey and thus learned A LOT. Through Aquanswers, Momchil shares knowledge about freshwater and saltwater aquariums with the people within this community.

1 thought on “Does Boiling Water Remove Chlorine and Chloramine?”

  1. My take is in water an 1 needs water change I have no chemicals if I boil water will it be ok after letting it cool to put in my tank

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