Is Reverse Osmosis Water Alkaline? Let’s Find Out!

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With all the hype surrounding alkaline water, it may be a trend you want to jump on board with.

And if you have heard about the benefits of reverse osmosis, you may be wondering if your RO system is producing alkaline water as it clears contaminants.

Well, while reverse osmosis creates some of the purest water to drink, purity and alkaline pH are very different things. Let me explain…

Key Takeaways

  • Reverse osmosis water is not alkaline.
  • Quite the opposite; it usually falls below 7 on the pH scale, making it a weak acid.

Is Reverse Osmosis Water Alkaline?

First of all, is reverse osmosis water alkaline?

No, reverse osmosis water is not alkaline. It actually sits at a pH under 7, so technically, it is a weak acid! While that may sound scary, it isn’t. Orange juice has a pH of 3, which is far more acidic than RO water, and we consider OJ to be very healthy.

So why is reverse osmosis water not alkaline? During the filtration process, RO does a super job of removing up to 99% of impurities from water, both the harmful pollutants, but also all the healthy minerals.

Magnesium and calcium are two dissolved minerals found in municipal water, which increase the water’s pH to make it more alkaline. Once these have been stripped from the water, the pH drops to under 7, usually around 6.5 in the case of reverse osmosis, and down to 5.5 when the RO water is then exposed to air.

pH scale

Why Does Air Make Reverse Osmosis Water Acidic?

After RO water is processed, it’s usually kept in a tank or poured into a container. This water then comes into contact with carbon dioxide (CO2) in the air. Pure water actually loves having dissolved substances in it and soaks up the first thing it is exposed to after filtration which is the carbon dioxide, creating carbonic acid and lowering its pH level.

Just from this, if the water sits for long enough, the pH can drop down to 5! The cool thing is that the water’s ability to absorb things is so strong that it won’t take much for it to change again. For example, as soon as the water enters your mouth, the pH will change and adapt to your mouth’s pH.

How You Can Test the pH of Your RO Water

If you want to test your reverse osmosis water to see how the pH changes, there are a few ways you can go about it.

pH Test Strips

pH test strips are the cheapest and easiest way to measure the pH of RO water. Simply soak the disposable plastic strips into the water and then wait for a few seconds. The pH level will be indicated by the color change that appears on the strip.

Digital pH Meter

A digital pH meter is another option. This will give a more precise reading than the test strips, though it is a more expensive investment, particularly if you are only testing your water occasionally.

Litmus Paper

Litmus paper is a very basic measurement of pH, indicating only if the water is acidic or basic but not showing you the exact number. It is inexpensive but not as precise as a digital pH meter or even a pH test strip.

Using Red Cabbage

Have you got some leftover red cabbage in the fridge? You can use that to test RO water pH. The color compounds in red cabbage change their color when exposed to acid. To test your filtered water pH with red cabbage, blend it with regular water, and strain the cabbage pieces. Keep the cabbage juice liquid in a clear container, and add some RO water. If the solution turns red, it means the RO water is acidic.

How Can You Make Acidic RO Water More Alkaline?

So now you know that RO water is not alkaline, and while it is not dangerous, some people still want to adjust its pH so that they are drinking alkaline filtered water. All that needs to be done is to get the minerals that were stripped from the water back in. You can do this in a few ways:

Add a Remineralization Filter

A remineralization filter is a small unit that you attach to the water exit line. It contains minerals like calcium and magnesium, which will increase the pH of the reverse osmosis purified water usually back into the 7-7.5 range.

Some RO systems even come with remineralization filters already attached.

Add Electrolytes Or Mineral Drops

You can add certain things to your RO water before you drink it in order to change its pH. Electrolyte mineral powders, mineral drops, or green powders will add alkalizing minerals to the water to adjust its pH. Simply add them to the glass or jug of RO water before drinking.

Add Mineral Rich Salts

Himalayan salt and other mineral-rich salts could raise the pH of your RO water. Add ¼ of a teaspoon salt to a gallon of water and let it sit a while before drinking.

bowl of Sea Salt Flakes

What Are the Benefits of Alkaline Drinking Water?

There are a lot of supposed benefits to drinking alkaline water, but as yet, they have not been adequately backed up by scientific research. A lot of people swear by it, however. Some say that it helps their digestion, reduces bloating and heartburn, improves energy levels, and can even slow aging and decrease cancer risk. If you are experiencing any of these benefits from drinking alkaline water, great!

It can make sense to remineralize your RO water, though, even if the research does not support these claims.

For one, what remineralization can do is make the water taste better. Reverse osmosis water is stripped of anything that can affect its taste and odor, so it is often described as flat tasting. Adding minerals back in can give it a bit of a boost.

Remineralization can also come with the benefit of increasing your intake of essential minerals. While most essential minerals come from food, having them in water can contribute around 5% more to your intake, which is not a bad thing, particularly if you don’t have the healthiest of diets.

If you have any thoughts about the question, is reverse osmosis 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.
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