What Is Reverse Osmosis (RO) Water? Find Out Here!

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Many people have started to wake up to the benefits of reverse osmosis (RO) water, and have been taking active measures to integrate it into their diets.

What exactly is reverse osmosis water, though?

If you’ve been wondering about that, this article is for you.

Key Takeaways

  • Reverse osmosis water is water that’s been purified using a reverse osmosis membrane.
  • Reverse osmosis water is often used for drinking purposes.
  • You can produce your own RO water at home using a reverse osmosis system or buy the water in store.

What Is Reverse Osmosis Water?

So, what is reverse osmosis water?

Simply put, reverse osmosis water is water that has been purified using a reverse osmosis membrane. This can be done either at home, or you can purchase reverse osmosis water pre-bottled. Given the declining costs of household reverse osmosis systems, it’s a good idea to consider investing in one if you’re interested in switching to RO water.

All things considered, reverse osmosis water can be much healthier than regular water. That’s because it lacks pretty much all impurities that you would normally find in your tap water and other drinking water sources.

Still, reverse osmosis does come with some minor disadvantages that are important to consider if you are about to switch to RO water permanently. As long as you pay attention to those factors, the change can be a very positive one in your lifestyle.

young girl opening reverse osmosis faucet

What Is Reverse Osmosis and How Does It Work?

Reverse osmosis is a process for filtering water that has gained a lot of popularity in recent years. It’s one of the simplest ways to filter water and is highly reliable. It’s also highly effective, removing pretty much all contamination. The fact that RO systems operate on such a simple principle also makes them easy to maintain.

Osmosis Working Principle

Normally, when you have two containers of water with different levels of impurities separated by some kind of porous barrier, water will naturally start to flow over to the more concentrated side. Given enough time, the level of impurities on both sides will equalize and the water movement will stop. This is called osmosis, and it happens all the time in nature.

Reverse Osmosis Working Principle

The basic idea behind reverse osmosis is, as the name implies, reversing the process of osmosis. Since this doesn’t happen naturally, some additional work is required.

Again, two water solutions are separated by a thin, semipermeable membrane, with pores that are so small that only water molecules can pass through them.

But this time, external pressure is applied to the solution with the higher concentration of contaminants. This reverses the natural flow of water molecules. They now move from the lower to the higher-concentrated side. In the end, you will have almost pure water on one side of the membrane and highly contaminated water on the other.

In real life, there are some exceptions, but in most cases you can expect your reverse osmosis water to be purified by as much as 99%. The extra pressure that’s required to overcome the osmotic pressure comes from your plumbing system. That, combined with the special RO membrane, is pretty much all you need to run a reverse osmosis system at home.

What Contaminants Does Reverse Osmosis Remove from Water?

Reverse osmosis is great at removing many types of contaminants from water. It can easily deal with most of the common types of pollutants you can encounter in tap water and even well water. These include:

  • Metals
  • Salt
  • Radiation
  • Certain pesticides
  • Microorganisms
  • Floating particles
  • Asbestos
  • Proteins and other organics

Is Reverse Osmosis Water Safe to Drink or Is It Bad?

Since reverse osmosis water is highly purified, it’s naturally safer to drink than regular water. You’re drinking pretty much pure H2O and nothing else. You might notice a change in the taste or smell of your water, but that’s always a positive sign. It means that various impurities have been removed from your water, making it cleaner.

There is one minor downside to reverse osmosis water, which some people might be affected by. Specifically, reverse osmosis purification does not discriminate between different types of impurities. This means that along with all the harmful stuff that gets removed from your water, you also get rid of some that are naturally beneficial. This mostly concerns minerals.

With that in mind, if you’re used to obtaining your minerals from your water, you might have to make some adjustments to your diet to compensate. Don’t worry though, there are plenty of methods you can use to remineralize your RO water. This includes adding minerals directly to your drinking water, or even adding a remineralization stage to your RO purifier.

woman sitting in front of water glass

There are also some strange rumors floating around claiming that reverse osmosis water is harmful because it leeches minerals from your body. This is complete nonsense. It’s likely the result of people getting confused by the fact that reverse osmosis removes minerals from water. While that’s true, drinking reverse osmosis water will not do anything to take away minerals you already have in your organism. You can rest assured that drinking reverse osmosis water is at least as safe as drinking tap water.

In fact, when you factor in some other aspects of reverse osmosis water – such as the fact that it gives you more control over your diet – it’s a much healthier alternative to regular tap water. You just have to pay attention to your body’s specific nutritional requirements and make sure that you don’t stray too far away from the norms.

How Is RO-Purified Water Different from “Regular” Water?

The main difference between reverse osmosis water and regular water is the amount of impurities it contains. As we explained above, reverse osmosis removes pretty much everything from the input water. This makes it purer than the water you might be used to drinking.

In most cases, removing contamination will also impact the taste and smell of water. This depends entirely on the exact types of contaminants you’re dealing with. This means that this won’t always be the case. However, if you’re unlucky enough to have water that’s particularly heavily contaminated, you might notice an immediate improvement in this regard.

Keep in mind that you might already be used to drinking reverse osmosis water without even realizing it. This is mostly the case if you regularly purchase bottled water. More on that below.

RO Water vs Soft Water

Because reverse osmosis removes minerals from water, it can also soften it. Reverse osmosis water is always softer than the original input water. However, you should not take this as an indicator that reverse osmosis can replace softening as a process.

The two processes – water softening and reverse osmosis – are quite different and use entirely different approaches to accomplish their goals. In general, reverse osmosis is not intended for softening water as a main application. What’s more, particularly hard water can even be harmful to your reverse osmosis system. That’s because minerals will start piling up on the membrane and eventually clog it.

If you insist on softening your water, you must do this as a separate step in your purification process. The water softener should be added before the reverse osmosis filter in the overall setup. Otherwise, you’d be putting extra strain on your reverse osmosis system, as we explained above.

RO Water vs Distilled Water

Of all methods available for purifying water, distillation is probably the only one that ranks higher than reverse osmosis in terms of purification strength. Simply put, distilled water is as pure as it gets.

So why don’t we use distillation instead of reverse osmosis? Simple – it’s a more energy-intensive process, and doesn’t scale well. There is no reliable way to distill water in a continuous, automated manner. You always have to do a lot of manual work, refilling boiling stations and so on. This is not the case with reverse osmosis, which runs on its own in the background with pretty much no intervention required.

The only real advantage to distilled water in this context is that it can be produced on the go. It doesn’t take much to set up a campfire and boil buckets of water. On the other hand, you can’t really bring a reverse osmosis system with you. This makes distillation the better option for traveling and other similar situations. For everything else, you should focus on drinking reverse osmosis water primarily.

RO Water vs Bottled Water

You may not realize this, but many bottled water producers actually use reverse osmosis in their plants. So if you are used to drinking bottled water all the time, you might already be consuming a lot of reverse osmosis water.

That’s not always the case though. In some cases, bottled water is just straight tap water. Other types are sourced from springs or aquifers etc.

That said, producing your own reverse osmosis water at home does have a huge advantage here. It doesn’t require you to lug heavy bottles of water from the store on a regular basis. And since you’re not using any bottles, you’re not contributing to environmental pollution. Even if you recycle your bottles, this is still not ideal to not using any of them at all. This means that if you’re concerned about the environment, reverse osmosis water can be a great choice.

The Pros and Cons of Reverse Osmosis Drinking Water

If you want a more comprehensive overview of what exactly is and isn’t good about reverse osmosis water, here is a list of the pros and cons associated with drinking it.

Pro: Pure, Clean Water with no Contaminants

The most obvious advantage of reverse osmosis water is that it’s pure and clean – pretty much as pure as it can get. Even if you don’t care about contaminants that much, you should still know that this will likely improve your overall health in the long term. You might not even notice the negative effects of certain contaminants until you’ve spent many years drinking that type of water.

Pro: Potentially Improved Taste and Smell of Water

While this is not always the case, reverse osmosis usually does improve the taste and smell of water. Once again, this might not happen in your case. But it is worth paying attention to the quality of your drinking water if you plan on switching to reverse osmosis. You might notice that you suddenly enjoy drinking water a lot more than before.

You might even be shocked by the difference if you’re used to drinking heavily contaminated water. Some people falsely believe that water doesn’t have a pleasant taste to it by default, when in reality they’ve just gone through their entire lives without trying any alternative.

Pro: Stop Buying so Many Bottles

If you switch to reverse osmosis water, you won’t have to buy any bottled water from the store anymore. Of course, this might not be relevant to you if you don’t buy any in the first place. But if you do, it’s good to know that you can make that change in your life pretty easily. It’s not just about carrying bottles and inconveniencing yourself.

By purchasing so much bottled water, you’re also contributing negatively to the environment. This is something else that reverse osmosis water can change for you.

Pro: Improved Hydration

Maybe you don’t enjoy drinking water too much. You’re not alone – many people are like that these days. But let’s face it, substituting with sugary drinks and other similar beverages is definitely not a healthy option.

Switching to reverse osmosis water might make you realize that water actually doesn’t taste as bad as you thought. This newfound pure, fresh feeling can make you more motivated to drink water on a regular basis.

Under Sink Reverse Osmosis System

Pro: Perfect Ice Cubes

This is, admittedly, a benefit that not everyone will care about. But if you like chilling your drinks with the occasional ice cube, that’s another point in favor of reverse osmosis water.

Have you ever noticed how ice cubes from tap water tend to leave a slight murky residue in your drinks once they have melted? What you’re looking at are contaminants. With reverse osmosis water, your ice cubes will be perfectly crystal clear. This is not just an aesthetic consideration. Those contaminants can sometimes impact the taste of your drinks without you even realizing it.

Pro: Control Your Diet More Precisely

If your water is heavily contaminated, then it probably includes large amounts of salts and other elements which play a role in your diet. This can make it more difficult to control your diet because you don’t know exactly how much you’re consuming of those elements.

This can be particularly tricky with things like sodium. With reverse osmosis water, you know exactly what you’re drinking. If you feel like anything else is missing from your diet, you can easily add it as a supplement.

Pro: More Budget-Friendly

If you insist on drinking purified water, reverse osmosis is pretty much the best method in terms of budgeting. You won’t have to spend that much money on bottled water, and the overall maintenance of a reverse osmosis system is not as expensive or complicated as with other types of water purification. And yes, this even factors in the initial cost of the system.

With all that in mind, drinking reverse osmosis water is much easier on your budget. After a while, you may not want to go back to drinking regular water just for this reason alone.

Con: Some Healthy Minerals Get Removed

As we mentioned above, reverse osmosis purification can be a bit too thorough in some cases. Reverse osmosis water lacks all of those healthy minerals that you would normally find in your tap water. This can even shift the balance of your diet if you are already used to taking in those minerals from your water.

You might need to look into making changes to your diet to compensate in that case.

Con: Some Water Is Wasted

An unfortunate side effect of reverse osmosis is that it wastes a lot of water in the process. The ratio is quite high. In some cases, you might waste as much as five gallons for every single gallon of purified water.

Fortunately, there are ways to repurpose reverse osmosis waste water. You can also filter it again to purify it additionally. There is no shortage of solutions to consider on that front, so don’t worry.

For most people, reusing reverse osmosis waste water is the most appropriate option. You can use it for various purposes that have nothing to do with drinking. For example, you can clean your floor, your clothes, your car, or even flush your toilet with it. You might also be able to use reverse osmosis waste water for watering your garden, although this should be done with some precautions in mind. Specifically, pay attention to the sodium sensitivity of some of your plants.

Con: Water pH Is Reduced

Reverse osmosis water has a lower pH level than regular water. That’s due to all the minerals that get removed. In most cases, this probably won’t matter too much to you. Slightly lower-pH water is not any less healthy than regular water.

The only exception is if you have a specific condition that might make you more sensitive to it. Once again, this is something you should discuss with your physician if you have doubts.

Con: It’s a Slow Process

Reverse osmosis water purification takes some time. But if you use a storage tank, you don’t have to wait for the process to finish every time you want to drink RO water.

The only disadvantage here is that a large storage tank can lead to your water developing a stale taste if it’s been in the tank for too long. You need to balance the size of your storage tank with the size of your household and the water consumption habits of those you live with.

Con: Reverse Osmosis Systems Can Be Bulky

You need to make some space for your reverse osmosis system if you want to enjoy reverse osmosis water. You won’t be able to see most of the system, as it will usually be under your countertop or somewhere close, but you would still need to make space for the dedicated faucet in pretty much all cases.

Still, even that isn’t as bad as some other water purification methods, which can be much bulkier and more inconvenient.

Where Can You Buy RO Water?

As we mentioned earlier, many brands of bottled water are actually reverse osmosis water. You should check the labels to verify that this is what you’re buying if you want to buy it premade. You might also have the option to buy reverse osmosis water by the gallon using your own containers. Obviously, this is not an ideal option if you don’t have a car or another similar mode of transportation.

You can expect to pay between $0.30 to $0.50 per gallon of reverse osmosis water at most self-service stations. In some places, it can be a bit more expensive – up to around $1.00 per gallon. This price might not be very attractive compared to some brands of bottled water, but at least you know exactly what you’re buying and have the freedom to organize your shopping around a larger purchase (e.g. you can bring a large tank with your truck).

And of course, you’re always free to purchase and install your own reverse osmosis system. This will allow you to produce reverse osmosis water on your own in any quantities you want. It’s also a convenient solution in terms of removing those annoying trips to the store from your schedule.

If you have any thoughts about the question, what is RO water, please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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