Reverse Osmosis Water vs Alkaline Water – Which Is Better?

This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.

Reverse osmosis water is often labeled as ‘healthy’ water, as is alkaline water, but that is about where the similarities end.

The two kinds of water are completely different.

So, alkaline water vs reverse osmosis water – is one better for you than the other? Let’s see!

Key Takeaways

  • Reverse osmosis water vs alkaline water – they are entirely different things.
  • Reverse osmosis water is water that is free of any contaminants and impurities. That’s why RO water is great for drinking. It’s usually slightly acidic.
  • Alkaline water is water that has a pH of above 7. It may or may not have been purified.

Reverse Osmosis Water vs Alkaline Water – Which Is Better?

Reverse osmosis water and alkaline water really cannot be compared as they are entirely different.

Reverse osmosis water is water that has been cleaned of almost any impurities and harmful contaminants in a process called reverse osmosis water purification. The goal here is to make contaminated drinking water safe and healthy. Being stripped from almost all mineral content, RO water tends to be slightly acidic.

Alkaline water is simply water with a pH that is higher than 7. It’s usually produced using an alkaline water filter, but it doesn’t have to be. You could also simply add sodium bicarbonate to your water and, boom, it’s alkaline. Using an alkaline filter to make alkaline water can have the advantage that some contamination might also be removed. Plus, many of these filters enrich the water with healthy minerals. Besides, many sources online claim that alkaline drinking water has additional benefits such as boosting your immune system, but more on this later.

Bottom line: If you want drinking water that is free from potentially dangerous contaminants, RO water makes a great choice. You can even install a reverse osmosis system in your home and filter your water supply yourself! Alkaline water enthusiasts claim a multitude of health benefits from drinking alkaline water. The purity level of alkaline water depends on how it was produced.

What Is Reverse Osmosis Water?

At a base level, reverse osmosis water is water that has been filtered through a reverse osmosis membrane, which removes pretty much all contaminants. While municipal water has been treated to be biologically-safe and free from certain substances, it does not mean that it cannot contain things like pesticides and heavy metals.

Running your drinking water through a reverse osmosis filter ensures that it is free of these contaminants and many more, but it also means that it is free of minerals such as calcium and magnesium. That’s why reverse osmosis water is acidic.

young girl opening reverse osmosis faucet

How does the RO filtration process work?

Reverse osmosis membranes contain microscopic pores that only very tiny molecules can pass through. Water pressure pushes your water through this membrane, but pretty much the only molecules that will fit through the pores are H2O molecules, and everything else gets left behind.

What Is Alkaline Water

So then, what exactly is alkaline water?

The alkaline water sold at health stores has usually been treated to have a pH of more than 7. This happens by adding certain minerals into the water that can raise the water’s pH, such as calcium and magnesium. You can also make alkaline water yourself at home by adding baking soda to it or using an alkaline water pitcher.

Some claim that drinking alkaline water can help neutralize acidity in the body, improve digestion, boost energy levels, and enhance the absorption of nutrients. However, these claims are mostly unsupported by evidence.

Reverse Osmosis or Alkaline Water – Differences

There really is no comparing the two, as they are vastly different things. Alkaline water has a pH higher than 7, and RO water is contaminant-free.

Reverse Osmosis Water Is Free from Harmful Contaminants and Beneficial Minerals

Reverse osmosis can remove over 99% of harmful contaminants from water, including nitrates, lead, arsenic, pesticides, chlorine, and chromium-6. However, this filtration method also removes beneficial minerals like calcium, which would help make the water alkaline.

Alkaline water may have received some form of treatment in order to reduce contamination, but it doesn’t have to be.

Reverse Osmosis Water Is Slightly Acidic

Due to the removal of alkaline minerals from the water and subsequent exposure to air, reverse osmosis is actually acidic, not alkaline. While this may sound scary, its acidity level is not strong at all, usually around pH 5.5-6.5. Orange juice, for example, has a pH of between 3 and 4, making it more acidic than reverse osmosis water.

Alkaline water has a pH of over 7, often up to 9.5, which means it is not at all acidic.

Reverse Osmosis Wastes Water

One downside to reverse osmosis is that the filtration process itself creates wastewater. Some systems are better than others and waste a lot less, but for the less economical devices, they can waste 4 gallons of water for every gallon that is purified. Alkaline water production, on the other hand, does not waste any water.

Not All Alkaline Water Systems Remove Contaminants

Alkaline water is not focused on contaminant removal. Some methods to alkalize water send it through some filtration media, but this media is designed to add minerals into the water, not to take anything out.

Some alkaline water pitchers might have a filtration step to get rid of some easier contaminants, but not all of them will, and most are lackluster when it comes to effectively filtering the nasties out.

What Are the (Health) Benefits of Drinking Alkaline Water?

Some have hailed alkaline water as an amazing cure for various health problems, ranging from joint pain to cancer. According to some, the water’s high pH level helps neutralize the body’s acid, thus promoting overall health and well-being. However, despite the hype surrounding the supposed benefits, there is no credible scientific evidence to back up these claims, particularly regarding the body’s pH level, which the body keeps in tight control.

Alkaline water has shown some effect for reducing acid reflux, and some drink it as they believe it tastes better. Drinking alkaline water is not likely to kill you, but relying on it as a cure may not be wise.

woman sitting in front of water glass

What Are the (Health) Benefits of RO Water?

There are various benefits to drinking reverse osmosis water, particularly if your water supply has high levels of dangerous contaminants. Drinking reverse osmosis water can provide the following:

  1. Water free of sediment, disinfecting agents like chlorine, volatile organic compounds, nitrite and nitrates, pesticides, herbicides, heavy metals, salts and minerals, bacteria, viruses – you name it.
  2. Better-tasting water and food, as RO water is free from any chemical tastes or smells.
  3. Environmental and financial benefits, as you will no longer purchase expensive bottled water and contribute to the single-use plastic epidemic.
  4. Salt removal from softened water (great if you are on a low-sodium diet).

If you have any questions about reverse osmosis vs alkaline 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.
Learn more about .


Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment: