Side Effects of RO Water & Their Perfect Solution

Reverse Osmosis is one of the most trusted methods of purifying water at home. And that is because RO purification provides the most comprehensive removal of all types of harmful impurities from the water so that you and your loved ones remain healthy.

The state of drinking water contamination in India has further increased the popularity of this water purification technique. If you are someone, already using a RO water purifier or planning to buy a new one, who has heard about some potential risks or side effects of RO water then this post is for you.

Some critics of RO purification claim that RO purified water is not suitable for your health because of mainly two reasons.

1. RO Purification Removes All Essential Minerals from Water
2. RO Purification Reduces the pH Level of Water

Let’s discuss both the above points in more detail.

1. RO Purification Removes All Essential Minerals from Water

It is a widely known fact that RO purification not only removes harmful contaminants like disease causing microorganisms and harmful heavy metals like lead, arsenic, mercury etc. but also removes some essential minerals like calcium and magnesium. This is because the size of the molecule of these minerals is larger as compared to water and RO membrane only permits water molecules to pass through it.

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Because of this fact, some people claim that since RO removes these essential minerals from the purified water, therefore RO water is not good for your health.

There is no denying the fact that minerals like calcium and magnesium are essential for our body and RO purification does remove these during purification. See WHO’s report titled Health Risks from Drinking De-mineralized Water.

But it is also true that no other water purification method is as effective and as widely used as RO purification.

So how can you continue drinking RO water without worrying too much about the possible side effects of de-mineralized water?

We will talk about this in the later part of this post, let us first briefly discuss another RO water disadvantage.

2. RO Purification Reduces the pH Level of Water

RO purification also reduces the pH level of water. When water is passed through a semi-permeable RO membrane, many organic and inorganic constituents fail to pass through, however gases like Carbon Dioxide (CO2) pass through the RO membrane. CO2 combines with the free Hydroxide ions (OH-) in water to form acidic Hydrogen Carbonate or bicarbonate ions (HCO3), while the Hydrogen ions (H+) fail to find any substance to react with as most of the impurities are removed through the RO membrane.

ph level of water

As a result, water has a positive balance of H+ ion, lowering its pH and making it acidic. The higher the amount of CO2 in your water, lower is the pH level.

However, your body does a great job of maintaining a near neutral pH of 7.4 at all times. When you drink slightly acidic water, it loses its acidity the moment it comes in contact with saliva in your mouth and food in your stomach.

If you have any health issues or are trying to lose weight, you should stop consuming acidic and sugar-added drinks. You should drink pH-neutral or slightly alkaline water for maintaining a proper acidic balance in your diet.

The later part of this post also talks about how you can increase the pH value of RO purified water to make it neutral or alkaline.

What is the Minimum Level of Minerals or TDS in Drinking Water?

Most of the countries around the world including India have defined maximum acceptable limits of inorganic and organic substances to assure the safety of drinking water.

minerals in water

Very little modern research has been done to set guidelines for the minimum quantity of minerals or TDS in water.

However, the importance of minerals and other beneficial ingredients in drinking water has existed for thousand years, being mentioned in the Vedas of ancient India.

Rig Veda clearly describes the properties of good drinking water as: “Sheetham (cold to touch), Sushihi (clean), Sivam (should have nutritive value, requisite minerals and trace elements), Istham (transparent), Vimalam lahu Shadgunam (its acid base balance should be within normal limits)”.

WHO report published in 1980, recommended that the minimum TDS in drinking water should be 100 mg/L. The optimum TDS should be about 200-400 mg/L for chloride-sulphate waters and 250-500 mg/L for bicarbonate waters. Water with a TDS of 25-50 mg/L was described tasteless.

In addition to the TDS levels, the report recommended that the minimum calcium content of drinking water should be 30 mg/L. The same report also reveals, European countries like the Czech Republic and Slovakia adopting the optimum magnesium level of 10 – 30 mg/L in the drinking water.

Possible Harmful Effects or Disadvantages of Drinking De-mineralized RO Water for Long

According to a WHO report published in 1980, de-mineralized water or low-mineral water is not considered ideal and its regular consumption may result in a deficiency of some essential minerals.

The study reveals that drinking water that is deficient in calcium or magnesium may result in several health consequences like a high risk of Cardio Vascular Diseases. The research also found that drinking water low in magnesium may be associated with a higher risk of motor neuronal disease, pregnancy disorders, sudden death in infants, and some types of cancer.

On the other hand, recent studies suggest that drinking water that has a low value of calcium leads to higher risk of bone fracture in children, premature birth and low weight at birth and some types of cancer.

Should You Stop Using RO Purifiers?

All the above studies seem frightening and you may now be thinking about stop using an RO purifier now.

But that is not the right solution, because if you stop using RO purifier then you will be at a very high risk of several life-threatening diseases caused by water impurities. Because no other water purification technology is as effective as RO purification.

The solution lies in overcoming the shortcomings of RO purification with the use of the latest technology. What this essentially means is a technology which re-mineralizes or adds back the essential minerals in the de-mineralized RO purified water.

The next section talks about how you can get water that has adequate quantities of essential minerals even with an RO water purifier.

How to Remineralize RO Water?

1. If you are already using RO water purifier (without mineralizer cartridge) and the TDS level of purified water is below 50 mg/L or 50 ppm then you can add an extra mineralizer cartridge after UV or post carbon filter, just before the water is filled in the storage tank. It can be done yourself or you can get this done from a professional.

Mineralizer cartridge like this one adds essential minerals like Calcium, Magnesium, Sodium, and Potassium to the purified water and make the water alkaline by increasing its pH value.

You can also buy special water bottles, called alkaline water bottles, which not only increase the pH value of water but also add essential minerals in water.

2. If you are planning to buy a new RO water purifier then always look for RO purifiers with mineralizer or TDS controller/modulator feature. This is especially important if the TDS level of raw/untreated water is below 900 mg/L or 900 ppm because most RO purifiers remove up to 90-99% of TDS. Several brands like Kent, Livpure, Havells, AO Smith etc. offer RO purifiers with TDS controller/modulator or mineralizer cartridge.

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You may also like to check out our post on Best Alkaline Water Purifiers.

3. Water is not the only source of essential minerals; several food items contain Calcium and Magnesium. You can include these foods to maintain the proper balance of these minerals in your body. Below we have listed some food items that contain Magnesium and Calcium.

Foods which contain Magnesium

  • Green leafy vegetables (e.g. spinach)
  • Fruits (figs, avocado, banana, and raspberries)
  • Nuts and seeds
  • Vegetables (peas, broccoli, cabbage, green beans)
  • Seafood (salmon, mackerel, tuna)
  • Whole grains (brown rice and oats)
  • Dark Chocolate

Foods which contain Calcium

  • Milk
  • Cheese
  • Yogurt
  • Almonds
  • Whey Protein


In the end, we would like to conclude all the debate around whether RO water is good for health or not with the fact that RO is not only the most effective purification technique but is also one of the safest. If you keep the simple things discussed above in mind then there is no need to worry and RO water is definitely good for health.

RO water purifiers not only give you access to pure water at affordable cost but also give you complete peace of mind that you or your family members would not have to worry about the purity of the water.

1 Comment
  1. I am personally completely unaware of these facts that RO purifier also removes some minerals which are good for health and how it works. Thank you for sharing useful information.

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