Should You Remineralize Reverse Osmosis Water? Let’s Find Out!

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No doubt, when researching reverse osmosis water systems, you have come across numerous sources stating that RO water is unhealthy unless you remineralize it.

It can be conflicting, as reverse osmosis is so thorough at removing dangerous contaminants, and surely that is better than keeping them in the water?

Let’s talk about whether you should remineralize your reverse osmosis water, and under what circumstances it may be absolutely necessary.

Key Takeaways

  • RO water is usually low in minerals. Low-mineral drinking water can increase the elimination of potassium, sodium, magnesium, calcium, and other minerals/ions from the body. That’s why the WHO recommends remineralizing low-mineral water before consumption.
  • The WHO recommends adding at least 20-50 mg/l (ppm) calcium and 10-30 mg/l (ppm) magnesium to low-mineral water.
  • That said, no more than 5% or so of minerals we ingest on a daily basis comes from our drinking water.

Should You Remineralize Reverse Osmosis Water?

So, should you remineralize reverse osmosis water? Yes, you should remineralize reverse osmosis water – at least generally speaking. By the way, this answer is based on a statement made by a WHO report.

That said, whether you should remineralize RO water or not really comes down to the individual.

It is important to note that with dietary mineral intake, only 5% or so of it comes from water, and most of it comes from your food. So, if you have a balanced diet, there might not be anything to worry about.

The other thing to consider is the quality of your feed water. If you have water that is highly contaminated with heavy metals, nitrates, or bacteria etc., reverse osmosis water without minerals will likely be the healthier option, as it won’t have the contaminants in it either.

Still, RO water is often low in minerals and low-mineral water can increase the amount of potassium, sodium, magnesium, calcium, and other minerals your body eliminates – which brings us back to our initial statement: The WHO recommends remineralizing RO water before consumption by adding at least 20-50 mg/l (ppm) calcium and 10-30 mg/l (ppm) magnesium.

woman sitting in front of water glass

Which Consumers Need to Add Minerals to Their Reverse Osmosis Water?

Everyone should consider adding minerals back into their purified RO water, but in some cases it is essential:

  1. Inadequate dietary intake of minerals – If you have a diet deficient in essential nutrients, then every little bit counts, including those you are getting from your drinking water. Remineralizing reverse osmosis water should be considered in diets that are not balanced.
  2. Malabsorption issues – If you have difficulty with nutrient absorption, then increasing your intake of vitamins and minerals is important. Mineral absorption issues can happen with surgeries such as gastric bypasses, conditions such as celiac disease, or simply can happen as you age.
  3. Taste preferences – Drinking reverse osmosis water may leave you with a bland taste in some cases. Remineralizing your purified water can give it a fuller mouthfeel and a better flavor.
  4. Reflux – If you are prone to reflux, you may want to consider remineralization, as it will stop your RO water from being acidic. RO water naturally falls to the acidic side of the pH scale, and while it is nowhere near the acidity level of, say, orange juice or coffee, if you are really sensitive, it could cause some reflux.
  5. If you use your RO water for cooking – There is some evidence to suggest that RO water will draw minerals out of your vegetables if you cook with it. This is not an issue if you are using your RO cooking water in a soup, broth, or stew, as the minerals will stay in the water and you will ingest them, but it may be an issue in cases where you discard your cooking water.

Generally speaking, the minerals removed from water during reverse osmosis are vital for optimal bodily functioning. Being deficient in these minerals can lead to brittle bones, fatigue, issues with blood pressure, cramping, kidney problems, and digestive issues, to name a few. So, if you do not think you are getting adequate amounts from your dietary intake, it is worth remineralizing your reverse osmosis water!

Why Can Reverse Osmosis Water Remineralization Be Beneficial?

Below is a list of reasons why reverse osmosis water remineralization can be beneficial.

Improved Taste

A lot of people describe reverse osmosis water as flat tasting. Minerals and dissolved solids in municipal water give it flavor, and as reverse osmosis removes all of those, the flavor goes too.

While this is a good thing if your water contains compounds that make it smell and taste bad, it might not be good if you enjoyed your water’s taste before you added the RO filter.

Improved Hydration

If you don’t like the taste of reverse osmosis water, then chances are you won’t be drinking enough of it. Remineralizing your water and giving it a bit more taste may improve hydration as it will be more palatable.

Reduced Rate of Mineral Elimination

As explained before, drinking too much low-mineral water can potentially cause your body to start expelling minerals too fast. Remineralizing your reverse osmosis water is a great way to prevent that from happening.

What Minerals Are Being Removed During Reverse Osmosis and How?

A home reverse osmosis system removes up to 99% of minerals from water. So, it removes pretty much all minerals with very high effectiveness.

The minerals are removed mainly by the process of reverse osmosis itself, where the feed water is pushed through a semipermeable membrane. This membrane allows only water molecules through and prevents larger contaminants from getting into the filtered water. They are left behind and flushed away with the waste water.

The minerals that reverse osmosis removes are many, but some of the main ones that are important in drinking water are calcium, magnesium, potassium, sodium, and phosphorus.


Calcium is an essential mineral for the growth and proper functioning of teeth and bones, the transmission of nerve signaling, and muscle contraction. Calcium is mostly removed during filtration with a reverse osmosis system.


Magnesium is a water-soluble mineral that plays a role in over 300 chemical reactions in the body, particularly in the nervous system, and is quickly depleted by everyday diet and activities. Like calcium, it is removed by the semipermeable membrane in the reverse osmosis process.


Potassium can help regulate the balance of water in the body, and plays a role in healthy muscle function. Dietary sources of potassium include fruits, particularly bananas, vegetables, and whole grains. It is removed by the reverse osmosis process with other minerals, such as calcium.


While sodium has a bad reputation, it is still considered an essential mineral. The negative health consequences, such as increased blood pressure and risk of heart attack and stroke, are only due to the excessive amounts of sodium found in the modern diet.

Sodium deficiency can cause exhaustion, muscle cramps, and headaches, and it is important for hydration.

young woman drinking water

Suppose you have been told to reduce your salt intake. In that case, reverse osmosis is highly effective at removing the sodium ions from your drinking water to ensure they are not contributing to your diet.


Phosphorus is vital in small amounts for cell maintenance, healthy bones and teeth, and muscle function. Phosphorus is too large to pass through the tiny pores of the reverse osmosis membrane.

How to Remineralize RO Water

There are several ways to remineralize your reverse osmosis water, the easiest being installing a reverse osmosis remineralization filtration step. There are also ways to remineralize it manually, but this comes with its own risks, as you need to ensure the right minerals are being added into the water in the right balance. You usually can’t just throw in a bunch of table salt and hope for the best.

The reason why the balance of minerals in drinking water is essential is because of electrolyte homeostasis. This is when the body tries to keep the balance of minerals in our bodies constant. When this balance is thrown off, it can lead to dehydration, cramps, or other health issues.

To prevent this from happening when remineralizing reverse osmosis water, you must ensure that the water contains a balanced amount of calcium and magnesium ions (and possibly others) and not excessive amounts of one or the other.

The ratios needed may also depend on your health status and own electrolyte balance; the WHO recommends adding 20-50 mg/l (ppm) calcium or more and at least 10-30 mg/l (ppm) magnesium.

Remineralization Filter

A reverse osmosis remineralization filter is an extra step added to your RO system to add minerals such as calcium and magnesium back into the water after it has been filtered and before it passes through your RO faucet.

This is probably the easiest method to remineralize your water as you don’t have to worry about how much of which mineral to re-add, and you don’t have to make jugs of water with salts or drops so that you have some mineralized water ready at all times.

The downside is that the remineralization filter will not be something that can be added to every model of reverse osmosis system, so check with your manufacturer.

Mineral Drops/Electrolyte Blends

Mineral drops and electrolyte blends are the next best thing to add to your water. This would involve filling a jug or container with RO water and then adding in the drops or mineral blend manually or adding them to each glass of water you pour before drinking, which can be annoying.

Alkaline Filter Pitcher

Alkaline filter pitchers contain a filter element that will add minerals to water as it passes through. It is an excellent way to remineralize without thinking about it much, but it means the only remineralized water you have access to is what is in the pitcher. Not ideal for things like cooking or for households that consume large amounts of RO water.

Mineral-Rich Salts

Mineral-rich salts are another alternative and budget-friendly way to add some minerals back into your water, but the debate is out on whether this is healthy. It involves manually adding mineral-rich salts such as Himalayan or dead sea salt into your water before drinking.

Some sources say that to remineralize the water properly, you would have to use an unhealthy level of salt and therefore increase your sodium intake too much to get the other trace minerals in, and some say it’s OK to add just a small amount, around ½ a teaspoon per gallon. So, with all the uncertainty, this probably isn’t the best option to go with. Plus, the risk of adding too much could mean messing up your electrolyte balance.

If you have any thoughts about the question, do I need to add minerals to reverse osmosis 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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