Reverse Osmosis Vs Distilled Water: Which Is Better?

Reverse osmosis vs distilled water_distilled water vs reverse osmosis

Reverse osmosis water filter systems and distilled water are commonly grouped in the same category. That’s because they both create some of the purest water possible.

The reality is there are significant differences between the two purification methods. In this article, we will compare and contrast reverse osmosis with distilled water. If you are on the fence over which one is best, don’t make your decision before getting the facts! Stick around until the end to see which tastes better, is healthier, and costs less.

The Basics Of Reverse Osmosis and Distilled Water

Let’s start by looking at what exactly reverse osmosis and water distillation are. Knowing how these two processes work will help to understand the positives and negatives of each. 

What Is Reverse Osmosis?

Reverse osmosis filtration is a process that uses high pressure to push water through a series of fine membranes to remove impurities. These membranes have a pore size as small as .0001 microns [1]!

Residential reverse osmosis systems can come in two forms. The first is a whole house reverse osmosis system that installs at the home’s point-of-entry. The second, and more common, is a point-of-use system. These can be either under-sink systems or countertop reverse osmosis systems.

After the water is forced through the semipermeable RO membrane, additional water is required to flush the system clean. This part of the process leads to reverse osmosis “waste water”, which we discuss in detail here.

Reverse Osmosis Vs Distilled Water_RO Membrane Diagram Infographic

The end result is purified water that can be up to 99.9% free of harmful contaminants [2]. The most common use for osmosis systems is to provide healthy drinking and cooking water.

What Are The Benefits Of Reverse Osmosis

  • Removes most water contaminants: Reverse osmosis is cited by the Environmental Protection Agency (EPA) as one of the most effective filtration options for eliminating all disease causing organisms and the most chemical contaminants. Most RO filtration systems exceed NSF/ANSI Standards in removing at least 95% of dangerous contaminants like lead, chloramine & chlorine, PFAS, fluoride, and more.
  • On demand filtered water: Getting access to filtered water with a reverse osmosis system is as easy as turning on the faucet. Since they are installed directly to your water supply you don’t have to wait for water. Unlike distilled water that is a little more involved and time consuming.
  • RO water is best for cooking: Once you start using RO filtered water for cooking you’ll notice a huge difference in the quality of the taste. Even chefs and restaurant owners use RO filtration systems saying that the water helps to enhance the flavors and textures of their ingredients.
  • More eco-friendly: We already have a huge problem with plastic bottle waste. Eliminating that in your household by investing in an RO filtration system will go a long way in reducing single-use bottles. Using drinking water from your RO will also cost less than consuming bottled water.

What Are The Disadvantages Of Reverse Osmosis?

  • Requires installation: Point-of-use RO systems require a little installation, unlike countertop water distillers that you simply plug into an outlet. That said, there are also countertop RO systems that required no plumbing modifications or installation.
  • RO waste water: Critics of using RO filtration systems will say they “waste” a lot of water. The average reverse osmosis systems have a waste water ratio of 4:1. This means for every one gallon of purified water you will use 4 gallons of waste water. Thanks to technology advancements there are now high efficiency tankless RO systems that have a 1:3 ratio. That means for every 3 gallons of filtered it only uses one gallon of water. Much better!
  • Removes healthy minerals: Reverse osmosis is so effective at removing a wide range of contaminants that it even removes the healthy minerals! Just like with distilled water, the end result is water that lacks minerals that are good for you like calcium, magnesium, and potassium. However, there are many reverse osmosis systems that remineralize your water at the end of the process. Remineralization ROs utilize a separate filter to finish the purification process by adding back the minerals so the end result is healthy pH balanced water.

What Is Distilled Water?

Distilled water was the original water purification process used to treat seawater to make it drinkable. Chances are you’ve heard of or even consumed distilled water because it’s readily available these days.

Distillation is the process of heating water to its boiling point, creating steam where it then cools back down to a liquid state to be collected. As the water turns to steam it leaves behind bacteria, minerals, and contaminants. Water distillers will remove 99.9% of total dissolved solids (TDS), inorganic compounds, and chemicals from water.

Home water distillers generally come in a compact countertop unit that is easy to set up. They have become increasingly popular due to their ability to remove even the most difficult contaminants. Countertop distillers have a boiling chamber where water is poured into and heated to a boil. The steam rises through a condenser where it leaves behind fluoride, arsenic, lead, and more before converting back to a liquid state. As the waster flows into the collection vessel it flows through an activated carbon filter to remove any remaining contaminants.

What Are The Benefits Of Distilled Water?

  • Creates the purest water: Distilled water when pared with a post carbon filter is amongst the most pure water you can have. It will remove 99.99% of total dissolved solids and bacteria from your water [3].
  • Doesn’t use chemicals: Distilled water uses the same process that the earth uses to purify and distribute water. Just like the hydrologic water cycle, a home water distiller does not require chemicals or come into contact with harmful materials to create pure water. It is an all natural process so you can even make distilled water at home with a DIY process.
  • Easy setup: Water distillers for home are compact and easy to set up. Most units are countertop distillers that you take out of the box, plug it in, and your’e off. There are even some distiller that require no electricity so they can be used on a stove top or fire for emergency preparedness.
  • Prevents scale buildup: Because it is free of hardness causing minerals, using distilled water wont cause scale buildup on your appliances. That is why using distilled water to clean CPAP machines is widely used. Distilled water also won’t cause corrosion on metal or automotive components for cleaning.

Related Article: Best Water Distillers

What Are The Disadvantages Of Distilled Water

  • Distillation removes even good minerals: Since distillation effectively removes a broad range of contaminants, it removes healthy minerals that our body needs. Through the process, minerals like calcium, potassium, and magnesium are left behind [5]. Although you should be getting most of your minerals from food intake, distilled water is not best to drink when exercising because it lacks electrolytes.
  • Not energy efficient: Distilled water vs reverse osmosis is not as energy efficient. Since home distillers require boiling water until it turns to vapor, a meaningful amount of energy is required. Not only that, but the distilling machines can create a lot of heat. If you are trying to distill water in your home on a hot summer day, it might not be ideal.
  • Distilling water takes a long time: Distilling water is not a fast process. The average at home water distiller will take four to six hours to distill one gallon of water. When you compare distilled water vs reverse osmosis that has water on demand, that is a long time to wait.
  • Unique taste: Distilled water will taste flat since it doesn’t contain any minerals. This isn’t necessarily a bad thing, but it’s an acquired taste. Some even prefer it to normal tap water or for using in their coffee.

Is Reverse Osmosis Vs Distilled Water Better For Your Health?

To start with, both reverse osmosis and distilled water are safe to drink. The most common pushback against both water purification options is they remove all the healthy minerals. But there are solutions for both.

We would argue that remineralizing reverse osmosis water is an easier process. There are reverse osmosis systems that come with remineralization filters included. After the reverse osmosis filtration process is completed, the mineral filter adds back good minerals like calcium, phosphate, and potassium. If you already have an RO system, you can purchase a mineral filter separately and easily incorporate it with your existing system.

Distilled water on the other hand does not have that luxury. There are ways to remineralize distilled water, but it isn’t done automatically like the RO systems. Our favorite solution to add minerals to distilled water is the Quinton mineral drops.

You also need to be cautious of where you are storing your distilled water after collection. Because distilled water lacks nutrients, it can leach chemicals from storage containers. That’s why it’s recommended to store distilled water in a glass container. If you are in the market for a home distiller, be sure to choose an option that comes with a glass-holding container.

While the difference in minerals removal between reverse osmosis and distilled water is small, neither process is perfect for all applications. Distillation, however, does not remove volatile organic compounds (VOCs) or benzene as reverse osmosis systems do [4].

When taken in combination, reverse osmosis is certainly much more accessible and practical than distilled water.

Is Reverse Osmosis Water Distilled?

No, reverse osmosis is not distilled water. When you’re comparing distilled water vs reverse osmosis, you’ll notice that their processes are completely different. This is why reverse osmosis water can’t be called distilled.

Distillation means boiling water to get rid of contaminants, capturing the steam that rises from the water and allowing that steam to cool down and collected as your distilled water.  Simply put, you’re turning liquid into gas and back to liquid again to get an outcome. 

Reverse osmosis, on the other hand, works by forcing water through a semi-permeable membrane where it undergoes from a low concentration of solutes to a higher concentration of solutes that help remove dangerous contaminants. 

Our Final Verdict On Distilled Water Vs Reverse Osmosis

Which of these water purification options is best for your household? In this post, we covered the major considerations when comparing reverse osmosis vs distilled water. The good news is both methods create some of the cleanest water you can get.

Distillation is less energy efficient and takes much longer to produce. On the flip side, it is easy to set up and doesn’t require any chemicals. As an example, here is how you can make distilled water at home.

But if you’re talking about drinking water that’s not only clean but also healthy, a reverse osmosis filtration system is a much more reliable solution. You can have unlimited on-demand purified water right from your faucet.

At the end of the day, the verdict for reverse osmosis vs distilled water will depend on your needs, budget, and circumstances.  Healthy drinking water is more critical than ever these days and ensuring that your family has access to it is one of the best investments that can be made.

FAQs on Reverse Osmosis Vs Distilled Water

Here are some of the most frequently asked questions about distilled water compared to reverse osmosis:

Is distilled water vs reverse osmosis for CPAP better?

Distilled water to clean CPAP machines is popular because distilled water lacks all minerals. Therefore it will not create mineral buildup corrosion for cleaning CPAP machines.

Is reverse osmosis vs distilled water for humidifier better?

Distilled water for humidifiers is popular because distilled water has been purified of all harmful contaminants and bacteria. Because distilled water will not contain calcium, it won’t create corrosion within the humidifier components.

What is demineralized Water?

Demineralized water is water that has been stripped of its mineral properties. Reverse osmosis and water distillers remove minerals like calcium and potassium from water through the purification process.

Is distilled water safe to drink?

Yes, distilled water is safe to drink. Distilled water does not contain electrolytes like sodium, potassium, or phosphates. So while it is not harmful to drink, distilled water may not be the best water to drink during exercise. This is also what leads to distilled water tasting “flat”.

Article Sources

Freshnss uses only the highest-quality sources to support the facts used in our articles including: government organizations, independent studies, peer-reviewed journals, and lab testing results. Read our editorial review guidelines here to learn more about how we verify and fact-check our writing to keep our content reliable, accurate, and trustworthy.

  1. A Review of Reverse Osmosis Membrane Materials for Desalination, Journal of Membrane Science
  2. A Guide to Drinking Water Treatment Technologies for Household Use, Center For Disease Control (CDC)
  3. Distillation Treatment Systems for Private Drinking Water System, Connecticut Department Of Health
  4. Drinking Water Treatment: Distillation, University of Nebraska, Environmental Engineering Extension
  5. Dangerous Distilled Water?, University Of Illinois
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