This article was co-authored by Brian Blake and by wikiHow staff writer, Sophie Burkholder, BA. Brian Blake is an Aquarium Expert and the Owner of Boodleshire Aquatics based in the Kansas City Metro Area. With over 20 years of experience, Brian is an expert in freshwater planted aquariums, saltwater reef aquariums, and aquarium installation, care, and maintenance. Brian holds a Bachelor's degree in Ichthyology and Aquatic Environmental Science from Emporia State University.
There are 18 references cited in this article, which can be found at the bottom of the page.
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Whether you’re concerned about chlorine in your drinking water, fish tank, or garden, there are several quick and easy ways to remove chlorine from water. Natural methods like boiling or evaporation are useful for small volumes of water. Dechlorinating a large volume, though, will probably require the use of an additive. Or, you could invest in a filtration system to remove chlorine at the source and save yourself some time. Whatever your preference, we’ll give you the information and the simple steps you need to dechlorinate your water—along with pro tips from aquarium experts Brian Blake and Cyriac StVil.
Removing Chlorine from Water
The easiest way to get chlorine out of your water is to boil the water for 15-20 minutes. Let the dechlorinated water cool to room temp., then store it in the fridge. Alternatively, you can purchase a pitcher with a water filter or even a reverse osmosis or activated carbon water filter system under your sink.
Steps
How to Remove Chlorine from Tap Water
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Boil chlorinated water for 20 minutes, then refrigerate it in a clean jug. Boiling creates heat and aeration (via bubbles), the combination of which is sufficient to remove volatile chlorine after 20 minutes. After boiling, let your water cool to room temperature, pour the cooled water into a clean container, and store it in the fridge. For small batches of water, boiling is probably the quickest and most effective way to get rid of chlorine.[1]
- If you’re trying to dechlorinate large batches of water, however, this method is probably not the most practical.
- Boiling for at least 20 minutes will also remove chloramine, which is used instead of chlorine in some towns.
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Let the water sit for at least 6-7 hours so that the chlorine evaporates. Fill a pitcher, bucket, or tub with the water you want to dechlorinate. Leave the container uncovered and place it in an area with limited airborne particles and debris to prevent contamination. If your container is small enough, you can place it in the fridge, although this may slow the dechlorination process. “Let [the water] sit in the open and let the chlorine and chlorine gas” dissipate naturally, instructs Blake. Check the water regularly using a chlorine test kit to determine how much chlorine remains in the water.[2] .
- The precise length of time needed to dechlorinate water depends on a number of factors. Firstly, the amount of volume you’re trying to remove—a pitcher of water will likely take 6-7 hours to dechlorinate, while a large tub may take up to 24 hours or more.
- For larger amounts of water, a wider and shallower container will hurry the process along (versus a deep, cylindrical receptacle).
- Also, placing the container in direct sunlight will speed up the dechlorination process. While you may choose not to do this because you’re worried about dirt and debris, placing the water in sunlight will help to dechlorinate it faster.[3]
- Evaporation won’t remove chloramine, which is used instead of chlorine in some water supplies. It’s also not recommended for drinking water since contamination can easily occur. If you’re not sure whether your water company uses chloramine, ask them for a copy of the Consumer Confidence or Annual Water Quality Report.
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Use sunlight or an artificial ultraviolet light to dechlorinate water. Place the water you wish to dechlorinate as close as possible to a UV light source (your light source could be the sun or an actual UV heat lamp). Leave your water under the UV light for at least 24 hours, but make sure it’s not exposed to other contaminants or debris.[4]
- The precise amount of time it will take to dechlorinate your water depends on how much water you’re trying to dechlorinate, the strength of the light you’re using, and the presence of organic chemicals in the water.
- Use a chlorine testing strip to regularly check whether your water has fully dechlorinated or not.
- UV light will remove chloramine as well as chlorine. UV exposure is also a suitable dechlorination process for drinking water.
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Add 1 tsp of vitamin C (ascorbic acid) per 1 gallon (3.8 L) of water. Powdered ascorbic acid (also known as vitamin C) neutralizes chlorine. Just sprinkle 1 teaspoon of ascorbic acid over 1 gallon (3.8 L) water and mix. This method works best for dechlorinating water meant for plants or hydroponics systems, but it’s also suitable for dechlorinating drinking water.[5]
- Ascorbic acid is affordable and can be obtained from most pet or grocery stores.
- Ascorbic acid removes both chlorine and chloramine.
- Another option for chemical neutralization is potassium metabisulphite, which often comes in the form of a Campden tablet. To use this method, drop a 1⁄2 ounce (14 g) Campden tablet into 20 gallons (76 L) of water and let it sit for 1-2 minutes. For different quantities of water, check the package instructions.[6]
- While potassium metabisulfite is an easy option that’s effective for large quantities of water, many people dislike the idea of adding chemicals to their water, so they avoid this option.
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Install a water filter in your home or use a filtering pitcher. Water filters effectively remove chlorine from your tap water as it comes out (so you don’t have to dechlorinate every batch of water that you use). You can find water filters that attach to pitchers and faucets or are installed under your sinks. More advanced filters can be permanently fixed, so they’ll filter chlorine out of your entire water system. There are a few different types of water filters you could use to remove chlorine, including:[7]
- A reverse osmosis filter: Reverse osmosis refers to the process in which ions and particles are removed from the water. Reverse osmosis systems can be installed directly beneath your kitchen sink or where your water supply enters your home, and are therefore very convenient relative to other dechlorination methods. But they’re also very expensive, often reaching several thousand U.S. dollars.
- An activated carbon filter: Activated carbon is a special filter media that removes chlorine, chloramines, and organic compounds from water. Some activated carbon filters can be connected to your home’s water supply, or you can buy a filtered pitcher that uses an activated carbon filter. Activated carbon filters remove both chlorine and chloramine.[8]
- Whatever filter you choose, it’ll need to be changed at certain intervals. Check your manufacturer's directions to find out how often you need to change your water filter.
How to Keep Fish Tank or Pond Water Dechlorinated
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Add a dechlorination agent to remove chlorine and chloramine. You can buy dechlorination agents (also known as water conditioners) at any pet store—look for a conditioner that specifies that it works on chlorine and chloramine. “The easiest way to use a dechlorinator,” advises Blake, “is to use it as directed and stir it up in the bucket. If you’re adding it directly to the tank, you want to add the amount that fits the tank volume, not the amount of new water you’re adding because you need that liquid to distribute throughout the entire volume of the tank.” The water will be ready for immediate use.[9]
- StVil recommends dechlorination agents as the best “way to properly get chlorine out of an aquarium…some of the best anti-chlorinators and water conditioners are things like Stress Coat.”
- If you’re using the water in a fish tank with a biological filter, choose a dechlorination agent that doesn’t have an ammonia remover, which could cause problems in your filter.
- You can also remove chlorine from water before adding it to your fish tank by using the same methods you would use to remove chlorine from drinking water. For instance, you can purchase UV-purified bottled water, use a water filter, expose the water to a UV light, or mix vitamin C into the water.
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Aerate fish tank water using an air pump. You should always dechlorinate aquarium water before adding it to a fish tank, but aerating the water will also aid in removing chlorine continuously. Fish tanks typically require an air pump to circulate the water, so you’ll get an aerating and chlorine-removing agent as a bonus.[10]
- Buy the appropriate pump for your tank’s size and type, as well as the pets you’ll be keeping in the tank.
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Install an aerating sprayer for your fish pond. If you’re trying to dechlorinate pond water, use a spraying device (like a spraying nozzle connected to a hose) to add air into the water as it enters the pond. Chlorine is volatile and will naturally dissipate in open ponds, but aeration will speed up the process considerably.[11]
- Aeration does not work for chloramine, however, which is a less volatile additive used by some municipal water authorities. You’ll need to add a dechlorination agent as well.
Community Q&A
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QuestionSince chlorine has a boiling point of -34 degrees, why does it require 20 minutes to remove it from water?Community AnswerThis is because it is in solution in the water. The boiling point of -34 degrees is for pure chlorine. Since it is in solution in water, the boiling point is irrelevant. The property you would need to look at in this situation is chlorine's vapor pressure, which tells you how fast it evaporates at a given temperature.
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QuestionHow do I make a carbon filter dechlorination system?Community AnswerYou can buy granulated activated carbon or a carbon block from a hardware store. You can also buy its casing from Ace Hardware.
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QuestionIf you boil water for 20 minutes, will that dechlorinate it?Community AnswerYes, but allow it to cool after. You may find it comparable to bottled water. It may still taste funny though.
Tips
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You can also purchase dechlorinated (filtered) water from the grocery store.Thanks
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Most dechlorination methods do not completely remove chlorine. Different fish and plant species have different tolerances for chlorine, so find out what level of chlorine is acceptable for your purposes and use a chlorine test kit to check the chlorine levels regularly if you're concerned about them.Thanks
Expert Interview
Thanks for reading our article! If you’d like to learn more about filtering water, check out our in-depth interview with Brian Blake.
References
- ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
- ↑ https://www.health.state.mn.us/communities/environment/water/factsheet/chlorination.html
- ↑ https://pubmed.ncbi.nlm.nih.gov/34652150/
- ↑ https://www.ncbi.nlm.nih.gov/pubmed/19909414
- ↑ https://www.fs.usda.gov/t-d/pubs/html/05231301/05231301.html
- ↑ https://www.lauterdaybrewers.org/water-chemistry/
- ↑ https://www.health.state.mn.us/communities/environment/water/factsheet/chlorination.html
- ↑ http://www.sfwater.org/modules/showdocument.aspx?documentid=4125
- ↑ http://animals.mom.me/dechlorinate-water-hermit-crabs-1504.html
- ↑ https://www.tfhmagazine.com/articles/aquarium-basics/aeration-and-oxygenation
- ↑ https://www.otterbine.com/our-blog/pond-aeration-101/
- ↑ https://doh.wa.gov/community-and-environment/drinking-water/disinfection/chlorination-drinking-water
- ↑ https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- ↑ https://www.sciencedaily.com/releases/2020/01/200128142744.htm
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7665061/
- ↑ https://www.health.state.mn.us/communities/environment/water/factsheet/chlorination.html
- ↑ https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- ↑ https://www.techgearlab.com/topics/kitchen/best-water-filter
- ↑ https://www.fdacs.gov/Consumer-Resources/Recreation-and-Leisure/Aquarium-Fish/Aquarium-Water-Quality-Sources-of-Water
- ↑ https://www.basny.org/id2699-taking-the-plunge-to-salt-water.html
- ↑ https://www.health.state.mn.us/communities/environment/water/factsheet/chlorination.html
- ↑ https://www.dep.pa.gov/Citizens/My-Water/PublicDrinkingWater/Pages/Chloramine-in-Drinking-Water.aspx
About This Article
To dechlorinate the water in your fish tank, stop by your local pet store and buy a dechlorination agent. Then follow the directions to add the right amount to your fish tank. If you want to dechlorinate drinking water, just boil it on the stove for 20 minutes. The heat and bubbles will remove the chlorine! For more ways you can dechlorinate water, like using an ultraviolet light, keep reading!
Reader Success Stories
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"The fact that you cannot use a pressure cooker, as it says to leave the lid off. This results in using pressure cooker like ordinary saucepan. (I was hoping that using pressure cooker would reduce boiling time). Thank you."..." more