Difference Between Reverse Osmosis and Distilled Water

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If looking for ways to purify your water, you’ll have to use either distillation or reverse osmosis water purification system. Both reverse osmosis and distillation are methods of purifying water. However, they function in very different ways.

Difference Between Reverse Osmosis and Distilled Water

So, what are the differences between these two water purification methods? Is one better than the other?

Understanding the differences between the two processes will help you decide on the method to settle for. That’s why in this post, we’ll take a look at the science behind and the differences between the two water purification methods.

We’ll help you get a deep understanding of both.

Reverse Osmosis Vs. Distilled Water – The Basics

Reverse osmosis is a common filtration process that forces water through a series of semipermeable membranes. It is used by lots of people to provide clean, filtered, and healthy drinking water.

Reverse osmosis is also used in industrial agriculture to control soil pH, food and beverage production, and the production of pharmaceutical products.

As a filtration process, reverse osmosis also ensures that no contaminants or condiments enter your drinking water. It helps remove minerals, salts, and microbes.

On the other hand, distillation is simply a process of boiling water, capturing the steam, and condensing it back into water. In other words, it is a process that involves turning water into gas and reforming it into liquid water again.

Distillation helps in removing contaminants and producing clean water. It is effective in removing dissolved solids like minerals and salts from the water.

The Differences

To help you understand the difference between the two water purification processes, we’ll look at the impurities that each removes from the water. We’ll also go through the pros and cons of each method.

1. Distillation

Distillation is actually a water purification method that has been used for the longest time. It operates on the principle of the natural water cycle and is seen to be 99.9% effective.

Impurities that water distillation removes

Distillation works on hard water and helps to remove soluble water impurities from the water. It also helps to remove heavy metals like mercury, lead, and arsenic. It also targets a wide range of herbicides and pesticides hence highly effective.

And as if that’s not enough, distillation also helps to remove bacteria, nitrates, dissolved solids, among other unwanted elements in your water.

Advantages of Distillation

Distillation helps to remove a wide range of impurities, including soluble and organic contaminants. It ensures that you have a constant supply of pure and clean water.

It also works to remove the hardness of the water. The water you get from this filtration process is also safe to consume directly. You won’t need to boil it for your family to drink. All you’ll have to do is fill your water bottle and place it in your top-loading water dispenser, and you’re done.

Disadvantages of Distillation

Although water distillation has plenty of benefits, it also has some downsides that you need to consider. Compared to reverse osmosis, distillation leads to high energy costs. Home distillation systems require high energy to run, resulting in increased expenses.

Distillation also takes a lot of time to produce enough water. For instance, if you were to filter 50 gallons of pure water through distillation, it would take you more time than when using a reverse osmosis system.

Another disadvantage is that most people don’t enjoy drinking distilled water. They term it as bland and argue that it has a flat taste. And this is true because distilled water is demineralized water (water with salts and minerals removed). Minerals and salt give the water some taste.

It also doesn’t remove chlorine from the water.

2. Reverse Osmosis

Reverse osmosis takes advantage of the phenomenon of natural osmosis in plants. Osmosis allows the movement of water from high concentration to low concentration.

In reverse osmosis, high pressure pushes water in the opposite direction (the process is reversed). It is forced against the natural concentration gradient as it goes from a lower concentration to a higher concentration across a semipermeable membrane.

The semipermeable membrane has very tiny pores (about 0.0001 microns thick). This feature allows it to catch up to 99% of the impurities in your water supply and allow water molecules to pass through.

Impurities that reverse osmosis removes

Reverse osmosis removes a lot of impurities, including heavy metals like lead, copper, magnesium, and sodium. It also reduces the amount of radium, sulfate, arsenic, and other harmful elements from the water.

It also helps to remove fluoride, herbicides, and pesticides from the water as well. And unlike with distillation, reverse osmosis helps to remove chlorine from the water effectively.

Advantages of reverse osmosis

Reverse osmosis helps to remove 99% of the impurities in your water. From heavy metals like lead and sodium chloride to dissolved solids, RO helps to remove them all. Its semipermeable membrane also helps to get rid of bacteria and viruses from your water supply.

RO also helps in delivering odor-free water without an after taste.

Disadvantages of Reverse Osmosis

During reverses osmosis filtration, a lot of water is wasted in the form of wastewater. The process also removes some good minerals from the water, which can lead to health problems.

Which is Better, Distilled Water or Reverse Osmosis?

If you want to water your plant that requires more acidic water, you can use distilled or RO water. You can also use the water if planning on growing your plants hydroponically (with roots in contact with water). All you need to do is add calcium or magnesium to the water to support your plants’ growth.

If you want to use the purified water for your aquarium, distilled water isn’t a great option. Remember that this process doesn’t remove chlorine from water. Chlorine will kill any lifeform in your aquarium.

Distilled water will also cause salts in the fish’s blood in your aquarium to diffuse into the water. Use tap water for your aquarium. If the only option available is distilled or RO water, just add the necessary salts and then use the water for your aquarium.


Distillation and reverse osmosis help to purify water but in different ways. Although effective, the distillation process is too slow, cumbersome, and leaves your water tasting bland. It is also inaccessible in most homes.

On the other hand, reverse osmosis is more cost-effective, fast, and accessible for all homes. It also offers a high level of protection against an unexpected rise in contaminants.

These systems target different impurities, and none is superior to the other. Ensure that you select one that addresses your needs.

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