Do Plants Grow Better With Tap or Distilled Water?

It doesn’t take a gardener to know that plants need water to grow. While it seems natural to water your plants to help them thrive, this seemingly simple task can go wrong in a few ways. The type of water you use is one of them.

Most gardeners recommend using distilled water rather than tap water. Distilled water is free of contaminants or other chemicals, making it safer than tap water, which may negatively impact growth (depending on where you live). It is purified water that provides plants with the hydration they need.

If you are still at a loss about which type of water to use, we’ll explain the debate to help you decide what is best for your plants.

Comparing Distilled and Tap Water for Plant Growth

Distilled water is believed to be better than tap water because it doesn’t contain any contaminants that can negatively affect your plants’ growth. Conversely, tap water contains chlorine, which is safe for plants in low amounts but negatively affects plants in high amounts.

Many studies have investigated the effects of distilled water and tap water on plant growth. One such study compared the effects of distilled water, magnetically treated distilled water, tap water, and magnetically treated tap water on tobacco plants.

The results showed that distilled water slightly increased the shoot and root sizes. In contrast, the two types of tap water caused physiological damage to the plants and may lead to stunted growth in your houseplants if overused.

I have used tap water often on my houseplants and know that this is the easiest solution for most people. However, if you’re not sure of the quality of your tap water, it is easy to understand why distilled water is recommended for plant growth.

If you’re still not sure whether it is worth the effort, take a look at the pros and cons of each option below:

Distilled Water

Pros

The pros of using distilled water include:

Void of Contaminants

Distilled water undergoes a distillation process that removes unnecessary and sometimes even harmful substances, such as metals, bacteria, and viruses. The process leaves you with pure water that is safe for human and plant consumption.

Safe for the Environment

The lack of contaminants makes distilled water safe for the environment. It doesn’t contain harmful elements that can leach off into the groundwater.

Use for Personal Consumption

Both humans and plants can benefit from safe and clean drinking water, which is another reason that distilled water is often a logical choice.

Cons

Along with those pros come some cons, such as:

A Higher Price

If you don’t have a machine for distilling water at home, buying distilled water for plants’ regular watering needs can be costly.

Lacks Essential Nutrients

The absence of contaminants means distilled water is also void of any elements that could sometimes be useful for plants in small amounts.

Tap Water

Pros

Some of the pros of using tap water for plants include:

Readily Available

Tap water is widely and readily available at home, making it convenient to water your garden plants directly. 

More Affordable

Your bills will be significantly cheaper if you use tap water instead of distilled water, even if you have a water distiller.

Cons

On the other hand, there are a few cons worth considering:

May Contain Contaminants

Depending on where you live, tap water may be contaminated with harmful bacteria and pollutants, even after passing the water treatment facility

Could Contain Toxic Levels of Chemicals

If you live in an area with many gardens or farms, chances are the ground contains leached chemicals that can enter the water pipes through cracks or breaks.

Drawbacks of Distilling Water For Plants

Although it is easy to see that using distilled water is far more advantageous for plants than tap water, you still have to consider the disadvantages.

Can Be Costly

Most households use tap water for daily cooking and drinking. Water from the tap generally undergoes filtration processes to make it safe for consumption, but some areas may have lower-quality tap water than others, depending on the source and how it is processed.

If you have plenty of houseplants or a massive garden that requires frequent watering with large amounts of water, distilled water is often not an option due to the cost. Therefore, you have to weigh your options and consider if the cost of using distilled water on your plants is worth it.

Time-Consuming to Prepare

Although plenty of reasonably priced home water distillers are available on the market, preparing distilled water can be time-consuming, especially if you are also using the water for personal consumption.

It can take several hours to generate enough distilled water for you, your family, and your plants every day. Larger distillers are available, but they can be even more expensive.

Plants Can Benefit From Minerals in Municipal Water

While distilled water is considered safer than tap water, we cannot deny that tap water also packs some benefits for your plants that distilled water doesn’t have:

Chlorine

The amount of chlorine present in tap water is typically safe and healthy for plants and people. This chemical is added to tap water during treatment to eliminate harmful microorganisms like bacteria and viruses. 

A chlorine concentration of less than four ppm in tap water is safe for human consumption. This value is also safe for most plants with short-term use, depending on how sensitive they are.

Good Bacteria

In addition to chlorine, tap water may also contain some bacteria that may be beneficial to plants. Bacteria serve as decomposers that feed on organic matter. These tiny organisms can convert and preserve nutrients that plants can use later.

However, these good bacteria may also be accompanied by harmful bacteria. That is why most people would prefer the water to be free from microbes altogether.

Final Thoughts

Distilled water is argued to be better for plant growth than tap water, and there are scientific studies to support this claim. However, there are some downsides to using distilled water, including cost and time to prepare. Consider the pros and cons to decide whether the benefits outweigh the disadvantages for you and your plants.

Dr. Moritz Picot

Dr. Moritz Picot is a horticulture enthusiast and the founder of TheGrowingLeaf.com, where he serves as the lead content writer. He established the website in 2022 as a valuable resource for both gardening aficionados and beginners, compiling all the gardening tips he has accumulated over the past 25 years. Alex has a passion for nurturing plants, transforming backyards into inviting spaces, and sharing his knowledge with the world.

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