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How To Dechlorinate Water for Plants – 2 Fast, Easy Methods

How To Dechlorinate Water for Plants – 2 Fast, Easy Methods

Many gardeners are unaware that their plants cannot withstand chlorinated water from the tap, leading to confusion when the plants begin to wither and die despite having water, light, and fertilizer.

When the plant finally succumbs to the excess chlorine absorbed by the roots, little does the gardener know that this was actually their own fault – a mistake that could have been avoided if they simply dechlorinated the water.

Before you water your plants, you need to dechlorinate the water and make it as close to rainwater as possible. So how would you go about dechlorinating water for your plants?

Read on to find out two easy ways that remove the harmful and poisonous gas from the water.

How To Dechlorinate Water for Plants: Method #1 – Let It Sit

1. Fill a Bucket With Tap Water

You can use a bucket or any other container. Just make sure that the container has a tapering shape like a cone.

The wide top speeds up the dechlorination of the water as it exposes a larger water surface to the sun.

2. Leave the Water in the Sun

Make sure that this is a bright and sunny day. Choose a sunny spot to keep the bucket full of tap water.

If the outdoor spot is also windy with good air circulation, that would be a plus. The idea is to let the UV rays of the sun interact with the water and release the chlorine gas faster. 

3. Check the Water After 24 Hours

Depending on the quantity of water in the container and the size of the opening of the container, chlorine might take 24 hours to 48 hours to evaporate fully from the water.

After 24 hours, check if the water still has chlorine. To test for the presence of chlorine, fill a test tube with water from the bucket and add 5 drops of orthotolidine (OTO – find it here).

If the color of the water changes to yellow, the water still has chlorine. Leave it for another 24 hours before testing it again. 

How To Dechlorinate Water for Plants: Method #2 – Boiling

1. Fill a Kettle With Tap Water

You can use a kettle or any other container to boil the water. If you need a lot of dechlorinated water for your plants, you can boil the water in a large pot.

Boiling tap water to dechlorinate it is a much faster process than simply leaving the water out in the sun. 

2. Bring the Water to a Boil

Turn the heat under the kettle or pot of tap water, and bring it to a boil. It’s important that the water starts to bubble up as the heat accelerates the release of the chlorine gas into the air.

Let the water boil for at least 5 minutes.

3. Let the Water Cool Down

After the water boils and all the chlorine is released out through the bubbles, let the water sit until it cools down.

Plants prefer the water to be either room temperature or slightly cooler than the air temperature. After the water cools down, test it for chlorine as I explained in the previous method.

Common Questions

Water splashing into a nearly full wooden bucket.

For the uninitiated, gardening can be a complex and sometimes confusing process.

The confusing part often has to do with why some plants can tolerate tap water while others would simply die from the presence of chlorine in the water.

If you’re new to gardening and you’re not sure whether your houseplants or outdoor plants can take your tap water or not, you’d better err on the safe side.

Make sure to dechlorinate the water before giving it to the plants. 

Chlorine Function in Plants

Ironically, chlorine is an important micronutrient that many plants rely on to function properly.

This is especially true of plants with green leaves where photosynthesis is crucial for the plant’s survival. In other words, most plants need chlorine. 

This chemical helps regulate the opening and closing of the pores on the leaves (stomata). This allows the plants to release excess gasses such as oxygen and carbon dioxide among others.

The presence of chlorine in moderate quantities in the plant ensures that the leaves stay firm and healthy.

Chlorine Deficiency Symptoms

Chlorine deficiency is a serious problem that interferes with the health of the plant and impacts its growth.

Since chlorine is crucial in regulating photosynthesis, the absence of the chemical causes the edges of the leaves to turn yellow. Severe deficiency leads to leaf bronzing and curling.

Effect of Chlorine on Plants

At the same time, excess chlorine can have negative effects on the plant. Since leaves store chlorine, too much chlorine leads to scorched or burned leaves.

If the plant doesn’t lose the excess chlorine, the chemical will damage the tissue of the plant, which can lead to wilting and the demise of the plant.

Is Tap Water Safe for Plants?

Most houseplants can tolerate tap water. The minuscule amounts of chlorine in tap water don’t affect the plants or cause serious problems.

However, some plants are sensitive to any amounts of chlorine in the water, so it would be a safe bet to dechlorinate tap water first or collect rainwater and use it to water the plants if possible.

Does Chlorine Kill Plants?

Although low levels of chlorine are important for the growth and health of the plant, too much chlorine can be toxic. In other words, if the plant absorbs too much chlorine, it can die.

At first, the leaves will become scorched due to the failure of photosynthesis; then, as more tissues are damaged, the plant will wilt and die.

How To Make Tap Water Safe for Plants

The best way to make tap water safe for plants is to dechlorinate the tap water.

You can either let the water sit for 24 to 48 hours to release chlorine or boil it and let the chlorine evaporate with the water bubbles.

How Long Should Tap Water Sit Before Watering Plants?

Ideally, tap water should sit for 48 hours to release all traces of chlorine. However, if you’re in a hurry, you can let it sit for 24 hours and test it before giving it to the plants.

Make sure the water container is sitting in a sunny spot with plenty of air circulation.

Should Tap Water Be Boiled Before Watering Plants?

Boiling tap water is usually the fastest way to dechlorinate it before using it to water houseplants.

However, you should let the water boil for at least 5 minutes. Then you have to set the water aside and let it cool down.

A woman using a metal watering can to water several houseplants.

How Much Chlorine Does Boiling Remove?

How much chlorine is removed by boiling usually depends on the concentration of chlorine in the water and the amount of water you’re boiling.

In general, if you have 10 gallons of water to boil with a chlorine concentration of 1 milligram per liter, then you need to boil the water for 3.7 minutes to get rid of that chlorine concentration.

To be on the safe side, boil the water for at least 5 minutes.

Do Houseplants Need Dechlorinated Water?

Most houseplants can tolerate tap water and will not show any signs of excess chlorine.

However, if the tap water is treated with a high concentration of chlorine to soften it, then it’s better to dechlorinate that water first.

Is Dechlorinated Water Best for Hydroponics?

Not necessarily. Dechlorinating water removes chlorine from the water, but if the tap water is contaminated with harmful chemicals, then it’s not ideal for hydroponic systems whether it’s dechlorinated or not.

I recommend using distilled water for hydroponics instead.

Does Bottled Water Contain Chlorine?

Chlorine is used to kill parasites and pathogens in the water that escape the filtering system.

However, bottled water doesn’t contain chlorine or any other disinfectants since the filtering process is more efficient.

Does Baking Soda Remove Chlorine From Water?

You can use baking soda to remove chlorine from the water. You can also use it to remove chlorine residue from your hair. It’s quite effective.

Do Plants Grow Better With Tap Water or Distilled Water?

Most plants will grow faster and produce more leaves if watered with distilled water compared to those that only get tap water.


Although many houseplants will have no issues with tap water, it’s better to dechlorinate the water to be on the safe side.

You can leave the water for 24 hours to dechlorinate it or bring it to a boil for 5 minutes to get rid of all traces of chlorine in the tap water.