Reverse osmosis: Facts and myths

Our body consists of 60% water. It is not surprising that the quality of drinking water is very important for our health. There are countless water filtration and treatment systems on the market, some of which are controversial to say the least. Such is reverse osmosis, also known as nanofiltration or membrane filtration. Find out for what purposes these filters are used, why the water produced in this way is definitely not drinkable, and also what are the correct methods of treating water.

How reverse osmosis works

Reverse osmosis, as its name suggests, is a water filter that works on principles of reversing the physical phenomenon of osmosis. These filters have an extremely fine membrane with a pore size of just 0.0001 microns, less than a millionth of a millimeter. Such membrane allows only water molecules to pass through, literally all other substances are catched by it.

So how does reverse osmosis work? During osmosis, demineralized water (pure H₂O) would flow through the membrane into normal water, i.e. water with a higher concentration of substances. But the reverse osmosis system exerts pressure on the water with dissolved substances, so that the water flows in the opposite direction. Ordinary water containing a wide range of substances flows to the membrane under pressure, behind the membrane there is only H₂O free of any substances and minerals.

Why is drinking water nanofiltration demonstrably harmful to our health?

Reverse osmosis sellers often offer these devices to households as well, to whom they promise "totally clean water" or "universal filter that solves all problems". Yes, reverse osmosis actually removes literally all substances from the water, which may sound great. However, the water may contain some harmful substances, but also a number of minerals that are vitally important for humans. Drinking water depleted of these substances is therefore a demonstrable health risk and is not recommended in any case – water produced by reverse osmosis is not drinkable, it does not even meet the EU limits for minimum content of certain substances in drinking water.

During cooking many times minerals are removed from the food, which reduces the daily intake of these substances even more. Reverse osmosis water is therefore not suitable for cooking.

Some devices operating on the basis of reverse osmosis have an additional function of "remineralization" of osmotic water, but the addition in this way is rather symbolic and cannot replace "ordinary" water.

Drinking reverse osmosis water causes a number of very serious health problems. Such water is not potable.

Health risks of reverse osmosis

Demineralized water is in fact distilled water, pure H₂O. After a longer consumption of such water, the human body suffers from a lack of calcium, magnesium, sodium and other substances, which negatively manifests itself in a highly increased risk of cardiovascular diseases and some types of cancer.

In addition, reverse osmosis water damages the intestinal lining and decalcifies bones, disrupts metabolism and leads to an increased risk of toxic effects of heavy metals. This water poses an extreme risk for pregnant women, where it can seriously damage the fetus and cause neurodegenerative disorders and other pregnancy issues.

​How to properly filter and treat water at home

If you have doubts about the quality of your water, first of all, have a professional analysis done. Only that will discover what pollutants your water may contain. Then, with the results in hand, contact an expert who will suggest a suitable solution for filtration and water treatment. Never rely on salespeople who may offer you a solution without any analysis. There is no universal solution and home water filtration must always be tailored to your specific needs.

In general, pollutants in water can be divided into 3 categories:

1. Mechanical impurities such as sand, rust fragments and other particles. These impurities do not pose a risk to your health, but they clog pipes and appliances. It is therefore advised to use a water filter with a mesh. Mechanical dirt filters are an integral part of domestic waterworks if you use water from your own sources.
2. Dissolved chemical and organic substances, for example chlorine and other disinfectants, but also fertilizers, chemicals from industry and transport, drug residue, heavy metals, etc. For such pollution, it is really necessary to get a domestic waterworks that can deal with a specific type of impurities. Most often (but not always) an activated carbon filter is used, which removes most of the dissolved substances, odors and turbidity from the water in addition to disinfection. Unlike reverse osmosis, activated carbon does not trap minerals, so the water is crystal clear and has an ideal ratio of all vital elements.
3. Biological pollution in the form of bacteria, viruses and microorganisms poses a health risk to humans and is commonly found in water from its own sources. The risk of contamination is minimal in waters for public sources, but not completely excluded. The solution is water disinfection. If you do not want to worsen the water quality with chemical disinfection, you can choose a much healthier and more ecological disinfection using special UV lamps.

Method of filtration and water treatment must be designed by an expert based on an independent water analysis from an accredited lab.

When can reverse osmosis be used?

It must be said that reverse osmosis has its practical uses, but not in households. Originally, this system was developed for seawater desalination in areas with a lack of fresh water resources. For these purposes, reverse osmosis is still used today.

Water filtered by reverse osmosis is also used as technical water or as lab water in chemical labs and in the production of pharmaceuticals. This water has its place, for example, in car heating and some appliances, such as air humidifiers and steam irons, where it prevents limescale formation. Reverse osmosis is also sometimes used in aquariums and industrial wastewater treatment.

Water produced by reverse osmosis has properties of distilled water and is not drinkable. But it is used in some industries. To improve the quality of water in your home, only use filters and waterworks that are suggested by an expert based on an independent analysis of drinking water.