How Long Should Tap Water Sit Before Watering Plants?

Every creature on Earth needs water to thrive and survive. So, watering your plants when they’re thirsty is an essential task. However, should tap water have to sit out before you use it on your plants, and if so, how long should tap water sit?

Tap water doesn’t have to sit for any time frame before watering plants. While many people believe that tap water should sit out for around 24 hours, that’s not always necessary. Allowing tap water to sit does eliminate any harmful chlorine, but it cuts out minerals your plants might need.

Opinions on this topic are split as some people water their plants and go about their day, but plant experts know there’s more to it. This article will discuss how long you should leave your tap water sitting before using it on your houseplants, why people do this, and if it’s necessary. 

The Myth Of Letting Tap Water Sit Before Watering Plants

I’m sure we’ve all heard the advice concerning leaving tap water out overnight before using it on your plants. Now, what if I told you that’s something you don’t have to do? That is correct- leaving tap water sitting before using it on your plants is a myth!

There’s no solid evidence of where this myth started, but plant enthusiasts have proved it untrue over the years.

However, there are still some benefits to leaving tap water to sit before using it, which I’ll go over next.

The Benefits of Letting Tap Water Sit Before Watering Plants

Although letting tap water sit out for a specified amount of time isn’t absolutely necessary, there are some benefits. Whether these benefits are worth it to you depends on what your plants need.

So, let’s explore what some of these benefits are.

Letting Tap Water Sit Regulates the Water’s Temperature

We all know from experience that it seems like our faucets only have two settings; the icy waters of the Arctic or the scalding lava of Mordor. It can be hard to get the right temperature for watering plants with no real in-between. 

Though some humans enjoy a nice cold burst of water in the morning to wake them up, plants don’t have the same appreciation for cold water.

Cold water can shock your plants, sending them into winter mode. Becoming shocked means that they’ll start to become dormant and will no longer grow or bloom. The good news is they won’t die, but you will have a hard time waking them up and getting them to bloom again.

Hot water can also shock your plants but in a different way. Hot water can make your healthy plants wilt and wither away, possibly even killing them.

So, leaving tap water to sit overnight can help get the water to room temperature, which is the perfect temperature for watering your plants.

Letting Tap Water Sit Eliminates Chlorine

I’m sure most people have had the traumatic experience of swimming in a pool and accidentally getting pool water in our mouths, noses, and eyes.

Additionally, most people know the experience of choking in the scent of chlorine as it burns your lungs, eyes, and nasal passages. 

However, it’s also known that chlorine disinfects water, which makes swimming pools safe. Its disinfectant ability is why chlorine is one of the chemicals added to tap water; so we can safely drink it without the risk of catching waterborne illnesses.

Despite this, chlorine can harm the growth and overall health of our plants. Plants watered with tap water might not grow to their full potential, and it could cause them to have fragile and brown leaves.

Spider plants are especially susceptible to fresh out the faucet tap water because they’re sensitive to chlorine. Carnivorous plants like Venus Fly Traps, Calatheas, Dracaenas, and Prayer Plants are also susceptible to chlorine.

So, to remove the chlorine from your tap water, let your tap water sit for 24 hours. Allowing the tap water to sit will make the chlorine evaporate from the water. However, you don’t need to do this if you have a filter attached to your faucet. 

The Drawback of Letting Tap Water Sit Before Watering Plants

While there are some benefits to letting tap water sit before watering your plants, it does have one drawback.

Tap water contains many minerals that plants need, and letting the water sit before using it on your plants can cause the minerals to diminish. 

Fertilizing your plants is an excellent and recommended way to help your plants grow to their fullest potential. Fertilizer is full of minerals and other nutrients to help your plants thrive and grow into luscious, gorgeous foliage.

Tap water is full of various chemicals and minerals, and guess what? Some of them can be found in fertilizer! Listed below are the common minerals found in both tap water and fertilizer:

  • Calcium
  • Chlorine
  • Magnesium
  • Potassium

Let’s get into how each contributes to plant health and growth:

Tap Water Contains Calcium

We all know how good calcium is for maintaining good teeth and bone health for humans. We also know it’s what helps make our cells, muscles, and nerves function properly. So, what benefits does calcium offer plants?

To start with, calcium reduces soil acidity, which is essential to ensuring your plants get the most water and nutrients they can without obstructions.

Calcium also aids in letting your plant better absorb nutrients, meaning your plant can grow to its fullest and healthiest potential.

Lastly, calcium improves your plants’ immunity to diseases. So if a disease starts spreading through your plants, the ones with more calcium are more likely to avoid getting the disease or avoid getting it completely!

Tap Water Contains Chlorine

I’ve talked a bit about chlorine and the traumatic experiences humans have with it when they go swimming. But for plants, chlorine can offer them a lot of benefits!

When it comes to ensuring your plant is being helped and not harmed by chlorine is to know if your plant is more susceptible to chlorine toxicity than other plants might be.

Above, I listed some of the plants that don’t do well with chlorine, and I encourage you to further research any plants you currently have or may want to own in the future.

The most vital thing to know about chlorine is which one to use for your plants. Yes, there is more than one type of chlorine, and which one you use makes a huge difference!

It’s better to use the chlorine ion (Cl) rather than the chlorine gas (Cl2) when it comes to plant care. The chlorine ion is a vital part of photosynthesis, allowing the plant’s pores to open and close so the plant can release carbon dioxide, oxygen, and other gases as needed. 

The chlorine ion also helps your plants maintain firm leaves, promoting a healthy-looking plant from the inside out! 

So being mindful of which plants are chlorine sensitive is essential, as is making sure you’re introducing the right kind of chlorine to your plants.

Tap Water Contains Magnesium

Magnesium is an excellent source for improving a person’s sleep quality, reducing the possibility of heart disease, and many other positive benefits.

So with all the fantastic things magnesium can do for the human body, what incredible benefits can it offer a plant’s body?

Magnesium is a crucial component in photosynthesis, which we all know is vital to a plant’s existence. Magnesium is essential to plants being able to metabolize the phosphorus molecule, which allows the plant to grow healthy and strong.

A magnesium deficiency can lead to your plants developing plant necrosis, growing slowly, and looking unhealthy in appearance.

So, make sure your plant is receiving plenty of magnesium to grow tall and strong!

Tap Water Contains Potassium

Most people are familiar with potassium, an essential mineral found in avocados and bananas. Potassium helps regulate fluid balance in humans and can help prevent strokes and high blood pressure.

Along with this, potassium helps produce higher-quality crops. Higher-quality crops mean that you will have more kernels on each ear of your corn. It also makes plants more resistant to drought, which is excellent when rain isn’t appearing in the upcoming weather forecast.

Additionally, potassium aids in photosynthesis and food formation. It helps increase root growth and your plants’ protein content, and allows them to retain water better.

So, if you’re a farmer or trying your hand at a vegetable garden, potassium is something you’ll want to keep in mind as you start planting.

To get all of these essential nutrients for your plants, you don’t need to let your water sit out overnight. I discourage you from leaving the water out for any timeframe if these nutrients are what you’re after!

Other Types of Water You Can Use on Your Plants

If you’d rather wait the 24 hour period to use your tap water, but your plants need watering now, don’t fret!

Watering the plants can be a time-consuming chore, especially if you have a lot of them! So waiting for any timeframe to water them might not feel worth the effort.

Here are some suggestions for other water you can use if you don’t have the time or patience to wait for your tap water to do what you need it to do:

  • Distilled water. Distilled water is boiled water that turns into a vapor and condenses back into a liquid. This process makes it purified water with no impurities left, making it an excellent option for watering your plants. The biggest downfall is this process can be time-consuming if you don’t do it ahead of time.
  • Rainwater. Rainwater comes from Mother Nature, so it’s the purest form of water you can use. It doesn’t contain chemicals, and it’s available to anyone on Earth! The only downside to this method is that if you don’t live in an area where it rains a lot, collecting rainwater will be more challenging.
  • Room temperature, pre-boiled water. Pre-boiling your water gets out the chlorine and everything else faster. The only downside is it uses up a lot of energy to boil the water.


The amount of time you leave your tap water to sit out depends on your plant’s needs.

If you need unchlorinated water, 24 hours is your magic number. If you need room temperature water, leaving it out overnight is your best bet. If you require additional nutrients for your plants, the winner is straight from the tap!

However, always be sure that you’re making the right water choices for your plants. Their health and well-being are more important than anything else.

You can read my guide on watering outdoor and indoor plants here: How To Water Outdoor and Indoor Plants (Ultimate Guide).

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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