What are the disadvantages of RO (Reverse Osmosis)? Why are these disadvantages still the top choice in the water purification market?

Reverse Osmosis (RO) is a widely used and highly mature water purification technology that filters impurities from water, including pathogens, heavy metals, and chemicals, to achieve high standards of drinking water. However, RO also has its drawbacks and advantages, which we delve into in-depth, discussing the commonly cited disadvantages of reverse osmosis.

1. Is it true that reverse osmosis water is unhealthy?

RO (Reverse Osmosis) filters can remove microbes, chemicals, and other impurities from water, but they also eliminate some beneficial minerals and trace elements. Because RO removes minerals and trace elements from water, drinking RO-treated water may lead to a deficiency in essential nutrients. Therefore, some experts recommend mixing RO water with water rich in minerals and trace elements.

But is this really the case? In fact, the minerals and trace elements filtered out can be obtained from food. Compared to the past when food shortages were common, people generally have a decent standard of living today, and cases of malnutrition are rare. In other words, excess nutrition is more common among modern people. Minerals and trace elements removed by RO filters include calcium, magnesium, potassium, sodium, fluoride, copper, zinc, manganese, and others, all of which are already proven to be sufficiently obtained through daily diet.

Take a more obvious example: according to the Food and Drug Administration’s food nutrition database, every 100 grams of cabbage contains the following nutrients:

Sodium: 11 mg, Potassium: 187 mg, Calcium: 47 mg, Magnesium: 12 mg, Iron: 0.4 mg. In contrast, the same 100 grams of mineral water contains only 0.02 mg of iron, magnesium, and zinc!

2. Why does the World Health Organization not recommend drinking?

Many experts (or non-RO manufacturers) will use this report as evidence to prove that ‘the World Health Organization does not recommend promoting RO (Reverse Osmosis) as daily drinking water.

Interested friends can download the full PDF report from the following URL: https://apps.who.int/iris/bitstream/handle/10665/43403/9241593989_eng.pdf?sequence=1&isAllowed=y

If we carefully read through this report, we will find that there are two misunderstood sections in this report.

(1)This is a report from the World Health Organization.

Therefore, its starting point is to reduce diseases worldwide caused by improper drinking water. Please note the key word “world”, especially in less developed countries in Africa, South Asia, and the Middle East, where people generally cannot obtain sufficient balanced food to sustain essential nutrition for life. Therefore, widespread adoption of reverse osmosis technology in these countries could potentially lead to some diseases. Consequently, this report also presents the advantages and disadvantages of other different water purification technologies, such as desalination and distillation technologies, compared to reverse osmosis. These water purification technologies not only retain minerals but also have the advantage of reducing energy consumption. Therefore, drinking reverse osmosis water is considered a more luxurious and unhealthy practice for these developing countries.

However, in Taiwan, the Treasure Island, where most people have no shortage of food and nutrition, we do not need to worry about diseases caused by lack of minerals and trace elements.

(2)The research period of this report spans from the year 1957 to 2004 AD

To put it simply, it is somewhat outdated and does not fully align with modern lifestyles. Consider, does Taiwan still have cases of beriberi today? Given the different time and context, this report’s relevance as a reference for Taiwan’s current situation far exceeds its practical significance.

The Chinese explanation of the above report is as follows:

‘Generally speaking, drinking water is not the primary source of important trace nutrients consumed daily, but serves as a supplement for these nutrients. The nutrient content in drinking water varies with geographical and geological distribution. Therefore, a balanced diet is the main source of these nutrients. For example, vitamin D can be obtained from milk, vitamin C from beverages, iron, vitamin B, and folic acid from bread, fluoride, and so on.’

Yes, you read that right. This explanation is clearly stated in this drinking water report, contrary to the one-sided interpretation that ‘RO reverse osmosis water is unhealthy water’.

3. Does reverse osmosis produce a large amount of wastewater, which is environmentally unfriendly?

The wastewater produced during the reverse osmosis (RO) process is an environmental concern because it consumes significant energy and water resources. Typically, RO systems can have a wastewater ratio of over 70%, which is a substantial waste especially in areas already facing water scarcity.

However, in recent years, new RO technologies have been developed with wastewater rates below 50%, reducing the amount of wastewater and increasing the production efficiency of pure water through RO. If you are still concerned about wastewater, you can also divert the wastewater pipeline separately for uses such as fish farming, watering plants, and washing dishes, which require less stringent water quality

4. Besides RO (Reverse Osmosis), what other water purification technologies can meet drinking water standards?

This is also a frequently compared topic. Apart from RO (Reverse Osmosis), there are other water purification technologies that can achieve drinking water standards. For example, hollow fibre membrane filter technology can filter out impurities from water while retaining minerals and trace elements. Additionally, ceramic filters, UV disinfection, and other technologies can also purify water.

Hollow fibre membrane is often compared with RO (Reverse Osmosis). Compared to RO, hollow fibre membrane filter technology retains minerals and trace elements in water, thus preserving the taste and nutritional content of water. Moreover, the operational cost of hollow fibre membrane is relatively lower and does not require substantial energy consumption.

However, it is important to note that these filters can achieve drinking water standards by reducing bacterial content and preventing diarrheal issues, but they cannot filter viruses and heavy metals.

5. Should You Purchase an RO Water Purifier?

Based on the above discussion, RO (Reverse Osmosis) is a technology effective in removing impurities from water, but it also removes beneficial minerals and trace elements and comes with higher operating costs. Other filtration technologies are relatively more environmentally friendly and cost-effective, but they have poorer filtration effectiveness. Therefore, the choice of water purification technology should be based on comprehensive consideration of local conditions and needs.

Who Should Use an RO Water Purifier?

• Large households with high water consumption needs.
• Those with higher standards for drinking water safety.
• Individuals with balanced daily nutrition intake, including regular consumption of fruits and vegetables.

Who Should Not Purchase an RO Water Purifier?

• Renters, as most RO systems require installation that may damage existing decor.
• Users who cannot accept wastewater generation or lack suitable wastewater drainage installation.
• Individuals with inadequate daily balanced nutrition intake.