Is Reverse Osmosis Water Good For Plants? (Why Not)

Gardening is a fun and relaxing activity, but with it, comes great responsibility. Whether you are just starting to think about gardening or looking for ways to improve your plants, you may wonder if changing the water will yield results in favor of your plants.

Now, this may lead to a question, “Is reverse osmosis water good for plants? Well, let us look into it.

For starters, water plays a major role in maintaining the health of your plants. Water not only makes your plants appear fresh and greener, but, at the same time, it may also be harmful to your plants if it is not treated well.

In the case of reverse osmosis water, fortunately, it can be significantly beneficial for your plants. In fact, it is the only water you should be using for your plant.

Reverse osmosis is basically a technique for water filtration. It was originally used for treating seawater to make it safe for drinking (desalination). It is used both commercially and in domestic water filtration systems.

It uses water pressure to pass H2O through a filtration media to separate solid particles, impurities, and even dissolved solids like salts and organic particles.

Over 99% of these impurities and salts are removed, thus leaving out a perfectly balanced water for your plants. So, technically speaking, reverse osmosis is the ideal water for plants and a must-have.

Continue reading to find out more about this.

Do Plants Like Reverse Osmosis Water?

reverse osmosis water ensures that your plants have a clean supply of water

Plants absolutely enjoy reverse osmosis water. This is due to the fact that water filtered through reverse osmosis does not have any heavy metals or any sort of contamination.

Due to the lack of these heavy metals and contaminations, the pH levels and nutrient ratios are also undisturbed -thus giving your plants an ideal environment for growth.

Using reverse osmosis water ensures that your plants have a clean supply of water and allows for better control of what your plants are receiving from the water.

What Type Of Water Is Best For Plants?

When it comes to watering your plants, there are multiple types of water. Here is a detailed insight into this.

Tap water:

Tap water is readily available in all households and many people simply use it to water their plants. But, unfortunately, tap water is not safe for some plants due to its sensitive nature. Tap water has multiple chemicals and when you use this water for your plants, it will damage them.

To cope with this, many people simply put tap water in a container and let it sit overnight. Most of the chemicals escape the water through evaporation thus leaving a slightly purified form of water.

But these chemicals are not entirely evaporated and have trace amounts in them. So, based on this, tap water is not recommended for your plants.

Distilled water:

Technically speaking, it is sort of a dead form of water. Every single nutrient or mineral in it has been removed by the process of boiling.

Although distilled water may seem good for our plants since it has all the chemicals and contaminants have been removed from it, at the same time the healthy minerals are also removed.

Cutting short, distilled water can be used to water your plants, but it will not be beneficial for your plants in any way whatsoever.

Rain water:

Rain water is filled with essential nutrients and minerals that keep your plants healthy and green. It also promotes healthy plant growth and will provide a significant boost to the overall quality of the plants compared to any other source of water.

But as you know, it is a no-brainer that rain fall only occurs occasionally. You cannot wait around for rain to water your plant even though it is the most beneficial form of water. So, you cannot merely rely on rain water and instead other forms of water will be fruitful for your plants.

Related: Is Rain Water Distilled?

Fish tank water:

If you have a fish tank around your house, you should know that it can be significantly beneficial for your plants. Albeit, not so much as the rain water, it still is beneficial for your plants. In fact, fish tank water has small amounts of fish and food waste, precisely making it a sort of fertilizer for your plants.

The only downside according to people is that fish water may be smelly. However, it is not the case since the unpleasant odor is too minimal to notice, so you’re good to water your plants with fish tank water.

Spring water:

Spring water is the second best to rain water when it comes to the nutrient and mineral composition. Spring water comes from natural sources and is entirely chemical-free; thus, making it safe for your plants.

Unfortunately, just like fish tank water, spring water also has a downside. It may not be available everywhere so you could not rely on it as your primary source of water for your plants.

Reverse osmosis water:

Reverse osmosis water is free from impurities including heavy metals, salts, and even chlorine. It is readily available and contains a heavy dose of the healthy minerals and nutrients your plants need.

In fact, people also prefer it over other forms of water since it does not react with fertilizers while at the same time providing an extra dose of nutrients.

So, all in all, reverse osmosis water is the one you should be using for your plants.

What Can I Add To Ro Water For My Plants?

Many reverse osmosis systems use regular water for purification and as you might know, it contains chlorine in it. Reverse osmosis system alone is not able to purify the water from chlorine and even the final product (RO water) may still contain trace amounts of chlorine in it.

To deal with this, you can add small amounts (1 block) of carbon to the reverse osmosis system to further lower the chlorine amount in RO water. It can effectively remove up to 98% or higher amount of chlorine from the water.

Do I Need Reverse Osmosis For Planted Aquarium?

RO water is soft and has no significant hardness. This makes it extremely pure for aquarium use. So, for planted aquariums, RO may not be as beneficial as for the plants in your garden. This is because due to the lack of certain essential nutrients in RO water, it may alter the pH of the aquarium water and end up with an unstable pH.

Alternatively, you can re-mineralize RO water for aquarium use. Here is how you can re-mineralize RO water:

  • Add 5 ml of water conditioner and a single teaspoon of baking soda in a container.
  • Mix the product well and add one quarter teaspoon of acid buffer (for approximately fifty gallons of reverse osmosis water).
  • Let it sit for a couple of minutes and the end product will yield re-mineralized RO water.

How Does Reverse Osmosis Work In Plants?

Reverse osmosis is a filtration system that works by passing water through a filtration media (membrane) thus removing impurities via the filtration membrane from water.

It essentially operates by reversing the process of osmosis, which is a natural tendency of water to flow via a membrane to alter the salt concentration. It is a naturally existent process (found in nature).

Plants work the same way and fulfil their water and nutrient requirements from the soil using this process. Whereas in humans, kidneys use the principle of osmosis to extract water from the blood circulating in the body.

How Does Reverse Osmosis Affect Plants And Vegetables?

Reverse osmosis affects plants and vegetables in a positive way. This is due to the fact that a reverse osmosis system significantly purifies water and lowers the number of contaminations in the water. Due to this, it is ideally used by gardeners that have a diverse collection of plants in their garden.

The most prominent advantage of reverse osmosis water is that it is not only clean and consistent, but also allows for better control of the nutrients and/or fertilizers your plants may need.

The second benefit of RO water is that it is pH adjustable. It can easily be varied for plants that have specific pH requirements. So, we can conclude that RO water also allows for better versatility in terms of adjusting the pH of water.

Tip: If you have chlorination, bacteria, or iron issues in your garden, reverse osmosis water is what you need to tackle with these issues. RO water is an alternate of rain water for your plants in this case.

Pros & Cons Of Reverse Osmosis Water For Plants:

Like everything else, reverse osmosis water also has its pros and cons. Here is an insight into this:


  • Reverse osmosis water is free from most contaminants. Reverse osmosis systems are extremely beneficial when it comes to removing disease causing bacteria and chemicals from the water.
  • Ro water allows for better control of nutrients. You can adjust the amount of nutrients easily in the RO water, thus ensuring an ideal growth environment for your plants.
  • With no iron, manganese, and calcium in the RO water, it ensures that the water will not react with the fertilizer and end up causing harm to your plants.
  • With reverse osmosis water, only the beneficial nutrients are provided to the plants and contrary to this, the harmful nutrients are removed.


  • Using reverse osmosis water for your plants may end up costing you a few more bucks compared to using tap or distilled water for your plants.
  • Reverse osmosis water sometimes may even end up not having the good nutrients so you will have to re-mineralize it, specifically in the case of aquarium plants.

Related Article: Will Distilled Water Kill Plants?

Frequently Asked Questions

You might already know this by now, but YES! Reverse osmosis water is absolutely good for houseplants. Since houseplants require a precise control of the nutrients and minerals they need, reverse osmosis water will safely allow you to do that.
It lacks the harmful chemicals that your tap water may contain such as chlorine and other contaminants. Due to this very reason, you should strictly resort to using reverse osmosis water for house plants.

Due to the lack of harmful contaminants and other pollutants found in regular water, it is perfectly safe for plants.
In fact, reverse osmosis may also allow you to have better control over the pH requirements of your plants. So, all in all, reverse osmosis water is what you should be using for the plants in your garden and your house.

The water that you get in your house is soft water. However, it also has certain amounts of heavy metals that need to be purified prior to watering your plants.
Now, when it comes to purifying water, your first thought would be to simply boil it. But, unfortunately, boiling the water will also remove the healthy nutrients that your plants need.
Based on this, it will be beneficial for you to use reverse osmosis instead. Returning to the original question, yes! Soft water with reverse osmosis is in fact, good for your plants.

Is Reverse Osmosis Water Good For Plants (1)

Conclusion | Is Reverse Osmosis Water Good For Plants?

Is reverse osmosis water good for plants? Yes, in fact it is the only form of water you should be using for your plants. While rain water and spring water is ideal for plants, reverse osmosis water is comparatively better than tap water, and distilled water.

This is because tap water may contain high amounts of chlorine and trace amounts of heavy metals, whereas distilled water lacks all of the healthy nutrients and minerals required by your plants. So, reverse osmosis water is what you should be using instead.


This is my blog about the ways and solutions that can help you improve your health by taking more value from drinking water. As improving health means a lot to me, I decided to create the Water On Top project with the purpose to reveal the benefits of water, the finest products to take our daily water to another level, and much more great stuff about water that I believe is on top of our nutrition.

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