How to Remineralize Reverse Osmosis Water

Written by: James Smith

Updated: March 15, 2023

Are you worried about the lack of minerals in reverse osmosis water? Learn how to remineralize water and add healthy calcium and magnesium back with our simple step-by-step guide.

How to remineralize reverse osmosis water

Reverse osmosis systems remove almost all harmful contaminants from water, providing a filtered result that is free of pollutants like chlorine and lead.

However, reverse osmosis technology is actually so effective that it strips all of the good stuff from the water too. That means while saying goodbye to toxic chemicals you are also cleansing the water of healthy minerals like calcium and magnesium too.

Should you continue to drink RO water? Should you remineralize the water before drinking? We take a closer look at reverse osmosis water and answer these questions, plus many more.

What Happens to the Water During Reverse Osmosis?

You may have heard of reverse osmosis, but do you really know what happens and what the end result is?

Here’s a quick run-through of the process.

In an RO filtration system, the membrane and filters are used to catch the water before it’s poured out. It’s filtration at its most basic, just on a microscopic scale.

The RO membrane allows water to pass through and into your glass but leaves behind anything with a larger particle size than its 0.0001 micron pore size.

To put that in perspective, 1 micron is equal to around 0.00004 inches and human hair is around 75 microns in width (source).

The semipermeable membrane catches and holds bacteria and impurities in the water, but it also prevents salt and other minerals from passing through too. This means that reverse osmosis water doesn’t contain the minerals you’d normally drink.

In areas where the water contains dangerous contaminants and is unsafe to drink, reverse osmosis can be quite literally a lifesaver. However, as a trendy health accessory in the western world, is it doing more harm than good?

Recommended Next: Don’t miss out on our awesome guide to the top whole home RO systems on the market.

metal minerals

The Source of Minerals

Humans don’t get most of their minerals from the water they drink; for the majority, food is the primary source.

Bearing this in mind, does it really matter if minerals are removed from our drinking water?

If you believe the World Health Organization (WHO) then, yes.

The WHO has released a report about what it believes are the dangers of reverse osmosis water and why it presents a problem.

According to research, if we drink demineralized water such as that processed through reverse osmosis, it will actually pull the minerals out of the food we eat. This is then urinated out of the body, reducing the amount that’s available for absorption.

The same process happens if demineralized water is used for cooking, such as boiling vegetables. The essential minerals are leached out of the veg, and into the water to compensate for the absence.

The amounts of minerals that are removed by demineralized water is substantial, as much as 60-70% of the total available. This leaves very little available for the body and is one of the reasons the WHO have said reverse osmosis water “has a definite adverse influence on the animal and human organism”.

Mineral water

The Minerals That Go Missing

Reverse osmosis has its roots in military applications where it was used to create a drinkable water source when contamination was present. From this very critical use sprung a more commercial one, with households using reverse osmosis systems to create purer water.

Some of the minerals which are extracted from the water include:


Calcium is the most common mineral in the body and makes up around 2% of the body’s weight.

As well as being present in teeth and bones, calcium plays a huge part in many of the body’s functions including your vascular and muscular contraction, blood clotting, regulation of enzymes and hormones and carrying messages between the nerves and the brain.

As calcium is involved in almost every process in the human body, a shortage can produce very serious effects. As well as resulting in weaker bones leading to fractures and osteoporosis, a calcium deficiency can also cause convulsions and potentially fatal heart arrhythmias.



Magnesium is another key mineral that is crucial for well-being and health. It plays a part in more than 300 biochemical reactions and is also involved in the development of healthy bones.

A typical human body contains around 25g of magnesium, 60% of which is found in the bones, with the remainder primarily in the soft tissues.

Magnesium levels within the body are very hard to measure because the majority of it resides within the bones. However, a deficiency could cause profound effects including weakness, nausea, and fatigue.

Continued deficiency could lead to numbness, cramps, seizures, personality changes and disruption to the rhythm of the heart.


Trace minerals

Although calcium and magnesium are the main minerals that are removed by the process of reverse osmosis, many other minerals are also filtered out.

This includes trace minerals such as fluoride, copper, chromium, manganese, selenium, iron, zinc and molybdenum iodine.

Does This Spell the End for Reverse Osmosis Water?

With minerals playing such an important role in the body, and reverse osmosis stripping away these elements, does it mean that filtered water should be avoided?

No, not necessarily.

Although the minerals in water are important for health, avoiding chemicals, bacteria and contamination is also very beneficial too.

The solution isn’t to avoid reverse osmosis but instead to add minerals to the water. This means remineralizing RO water so you can enjoy the benefits of contaminant-free water but still get the essential minerals the body needs.

If you’re wondering how to remineralize water, you’ve got a few different options to consider. Reverse osmosis remineralization isn’t as difficult as it might sound, but you’ll need to get special supplies first.

If you want to know how to make alkaline water with Himalayan salt, read on! Next, are some of the options for adding minerals to the water.


How to Remineralize RO Water

A lot of new RO systems for homes actually come with a built-in remineralization filter. This adds back those healthy minerals at the final stage before the water is poured.

However, there are a few other tricks to do this too.

  • Add a mineral-rich salt?

Himalayan sea salt contains elevated levels of beneficial minerals like calcium, iron, and magnesium. You can read a scientific study about the mineral content of Himalayan sea salt here.

A much-touted rumour (possibly started by salt companies?) has been widely spread across the internet about adding Himalayan sea salt to RO water in order to remineralize it.

The fact is, the amount of salt you’ll need to add to the water to make a difference is just too much.

The report I linked above concludes by saying:

“Despite the many nutrients found in pink salt that are essential for health, (e.g., calcium, iron, magnesium, and potassium), an exceedingly high intake of pink salt (>30 g per day) would be required before this made any clinically significant contribution to nutrient intake”

To put that into perspective, the WHO recommends you consume less than 5 grams of salt (2 grams of sodium) each day.

So, ignore the influencers that recommend adding a pinch of salt to each gallon of water. There are more effective ways to add minerals back to RO water.


  • Mineral drops for water

If you want to know how to add minerals to water without lots of work, this is one of the easiest solutions. You can remineralize any quantity of water quickly and easily by just adding a few mineral drops at any time.

A bottle of mineral drops should treat up to 200 gallons of water and cost less than $20 to buy.

  • Alter the RO water pH level with a filter

Remineralizing reverse osmosis water can be done at the source if you add an extra filter to your system.

A pH-balancing or remineralization filter can usually be added to most models without needing to replace the whole system.

After the water is filtered, some of the minerals are added back; just how much depends on various factors such as flow rate, water temperature and the existing pH level of the water.

Although there is evidence that this can increase the pH level of the water significantly, the level of remineralization can vary greatly.

  • Use an alkaline pitcher

You can also use a simple pitcher if you want to raise the pH level and add minerals back in.

There are several alkaline pitchers on the market that offer an easy way to remineralize RO water.

These pitchers change the pH level as well as remineralizing the reverse osmosis water. Some designs have built-in clocks that count down to the next filter change, a useful little extra.

RO Water – The Next Generation

Following the report from the WHO, reverse osmosis water has come under fire but the fact remains that it’s a useful way to access pure water that doesn’t contain chemicals or contaminants.

These types of filters provide reassurance to those worried about the medication residues which have been shown to reach the water supply. However, the new concern about the lack of minerals shouldn’t be disregarded either.

There are significant health benefits to excluding contaminants and chemicals from unintentional ingestion so reverse osmosis water still remains a valid option. By re-mineralizing the water, it’s possible to have the best of both worlds, receiving the valuable protection of the filter but still accessing the health benefits of minerals.

It’s fairly easy to remineralize reverse osmosis water once you know what to do. The key is to ensure that you only buy quality products to replace the missing minerals; don’t be tempted by substandard products on sale at the dollar store.

Stick to high-quality Himalayan sea salt or proper electrolyte and mineral drops, or invest in a filter or pitcher that is made by a reputable manufacturer. By doing this you can continue to enjoy delicious pure water with every health benefit possible.

Make sure to leave us a comment down below if you have any questions!

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About the Author James Smith

James is the chief water geek here at His mission is to empower the consumer and allow people to take control of their health. His passion for water health is contagious, hopefully unlike your tap water!

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  1. How can one be assured that the added minerals do not contain trace amounts of lead, arsenic, mercury? I used the product “Concentrace” for a while, which comes from Utah’s Great Salk Lake. Though it has overwhelmingly positive Amazon reviews, I lost confidence when I read a negative review in which the individual claimed to have tested the product and found it to contain trace amounts of lead and arsenic.
    The company responded saying that it is natural to have tiny amounts of these elements and they are not harmful in these quantities. Please advise.

    1. Those minerals occur naturally in certain soil/rock types so I can see how it happened. It’s none-the-less very worrying!

      The EPA and WHO provide safe drinking limits of these contaminants on their websites. Did Concentrace provide detailed numbers?

      I’d advise you to speak directly with one of the experts from the EPA for professional advice.

  2. Hi there,

    I live in Doha, Qatar – where I believe about 50 percent of the tap water comes from a number of desalination plants here. As a result, many people don’t believe the water is potable (despite assurances from the government and utilities provider), and so resort to ordering water in large plastic containers, through water coolers. I’m keen to avoid doing that – the country’s already the world’s highest emitter per capita, and I’d like to minimise the carbon (and plastic) footprint of my water consumption.

    I understand the primary danger in drinking the water here is the lack of minerals, as a result of the desalination process. What would be the best way to remineralise water for home cooking and consumption on a regular basis? I don’t see myself adding Himalayan salt to large vats in my rather small kitchen. Is there a filter or drops you’d recommend that I can try to procure from the Middle East or elsewhere? And/or would a terracotta filter add the requisite minerals?

    Keen to hear your thoughts!
    And thanks.

    1. Hi,

      We actually get most of our minerals from eating a healthy, balanced diet so the lack of minerals in water isn’t a huge problem.

      I’d recommend getting an alkaline filter pitcher. It’ll make the water taste better by adding some minerals back.

  3. WHAT IS HIMALAYAN SEA SALT? I THOUGHT THIS SALT COMES FROM THE HIMALAYAS. AT LAST CHECK THIS IS ONE BIG ROCK.So is Himalayan pink salt– a sea salt or a rock salt. i want to avoid microplastics and everybody knows they are found in sea salt

  4. what re mineralisation products would you recommend?
    If you use himalayan sea salt (or any others), how can you know you are adding enough?

    1. Hi Sophie,

      I would recommend testing with a relatively cheap kit available on stores like Amazon. This would enable you to judge how much to use and if it’s an efficient method for you.

    1. Hi Merri,

      As far as we know it’s fine. However, I’d seek the opinion of a medical professional to be sure.

  5. The RO systems I’ve looked at have a remineralization filter. One adds magnesium & calcium, the other adds those plus potassium. Is that enough for health, considering there are so many other trace elements that are removed from the water? I would be getting an RO unit specifically to filter out fluoride that is added to municipal water supplies. You’ve got fluorine (fluoride) listed as an essential element. The fluoride that is added to water systems is either fluorosilicic acid, sodium fluorosilicate, or sodium fluoride. How do these differ from the essential element fluorine, especially sodium fluoride, which is also naturally occuring?

    1. Hi William,

      The only way to be sure is to test yourself. It’s widely accepted that remineralization filters don’t add back as much as is removed though.

      We listed fluoride as one of the many natural minerals that is removed by reverse osmosis. Fluoride is naturally abundant in the ground and trace elements exist in all water. These trace amounts aren’t harmful, it’s the community fluoridation that poses issues.

  6. I add 15 grams Magnesium Chloride, 10 grams Calcium Chloride and 10 grams Sodium Bicarbonate to my RO water which gives me a PH of about 7.6 and was wondering if you could tell me how much Potassium Chloride I should add to 5 gallons. Also would really appreciate if you have different ideas as far as amount and which ingredients you might suggest.

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