What are the advantages and disadvantages of reverse osmosis water purifiers?
Are you thinking about buying a reverse osmosis (RO) water purifier, are you concerned about how RO works, are there better alternatives, and is drinking water produced by a reverse osmosis filter good for your health?
In this article, we explain the basics of reverse osmosis filters, their advantages and disadvantages, and the best alternatives to RO water purifiers.
What is reverse osmosis?
This technology was invented as a solution to
reduction of certain chemical contaminants, such as heavy metals.
Reverse osmosis is a process whereby water pressure is used to pass tap water through a semi-permeable membrane, which makes the water molecules relatively small and prevents larger molecules, such as dissolved minerals (like salt), from passing through. As a result, clean tap water and other substances in the water are separated.
A typical reverse osmosis system and its maintenance requirements are shown below, with a quick overview of reverse osmosis operation and troubleshooting starting at minute 13:35.
What does a reverse osmosis filter remove?
Reverse osmosis systems remove contaminants such as bacteria, viruses, nitrates, sulfates, fluoride and arsenic from water. However, they also remove healthy minerals such as magnesium, calcium, potassium and sodium. Reverse osmosis filters can remove more than 100 substances from tap water with a filtration efficiency of more than 99%. Some special high-pressure reverse osmosis filters, such as those from Blue Water, claim 99.99%.
In contrast, cheaper reverse osmosis filters are often significantly less effective. Therefore, it is very important to find out about independent laboratory testing and certification of each brand and product.
Reverse osmosis is not very effective for chlorination and water softening. Therefore, activated carbon filters should be used in combination with reverse osmosis systems in most cases. Activated carbon can also help remove more than 70 other contaminants, such as pesticides, herbicides, chlorinated biological agents and pharmaceuticals.
Reverse osmosis filters reduce TDS
Vendors use TDS testers to justify the need for reverse osmosis systems.
TDS is a measure of the number of dissolved solids in water. Sales engineers often cite this as a reason they need a water treatment system: the main components of TDS are usually calcium, magnesium and bicarbonate, which the body needs, and TDS is not an indicator of clean water. For example, a TDS value of 250 ppm usually means only that tap water has a high mineral content, which is positive.
Learn more about TDS as an indicator of water quality.
Do I need a reverse osmosis filter to drink clean water at home?
For the past 10-15 years, systems combining reverse osmosis and activated carbon have been marketed as the only solution for drinking water at home. Reverse osmosis filters can also be effective for domestic use. However, for public tap water in Europe and North America, reverse osmosis filters are often a waste of money and water.
Before you buy a reverse osmosis machine or other water treatment equipment, check the quality of your local tap water and what it takes to make it safe and tasty. Do not listen to the salespeople.
What are the benefits of a reverse osmosis filter?
- Proven technology for clean drinking water
- High-quality filtration of non-potable tap water that contains bacteria or heavy metals, for example.
- Can make tap water with very high mineral content (TDS 1500 or more) drinkable.
- What are the disadvantages of reverse osmosis filtration?
- Wastes up to six times more pure water than is produced (some products are much more efficient).
- Requires professional maintenance to ensure efficiency and safety.
- Removes healthy minerals such as calcium, magnesium, potassium and bicarbonate.
- Relatively expensive, from $300 + maintenance and replacement.
- Risk of bacterial growth in water after filtration because chlorine is removed.
- See our comparison between reverse osmosis and TAPP water filters.
Is demineralized water from a reverse osmosis filter good?
No, it is not. According to the World Health Organization (WHO), low mineral content (TDS) drinking water produced by reverse osmosis or distillation is not suitable for long-term consumption and may actually cause adverse health effects to consumers. This mineral deficiency can also have a negative impact on the taste of many people.
However, with a good diet, the minerals in tap water are not as important to you, so drinking demineralized water is not a problem.
What are the alternatives to reverse osmosis filters?
In Europe and North America, most tap water is already safe to drink (according to strict WHO, EPA and EU standards). Therefore, it is generally important to improve taste and reduce the risk of potential contaminants such as THMs, microplastics and heavy metals.
A high quality activated carbon filter solves this with the following benefits
Easy installation and replacement by anyone
Costs much less
Retains healthy minerals in the water
No water waste
Reduces the risk of water becoming rancid and tasteless.
An example of an activated carbon filter is the TAPP EcoPro.
For tap water with bacteria problems, there are also affordable ultrafiltration filters like Ultra TAPP Water, which removes 99.99% bacteria and over 100 contaminants.
Other alternatives to reverse osmosis include ion exchange, UV purifiers, ozone and distillation. Read more about water filters in this guide.
Reverse osmosis is an incredible technological innovation that uses seawater to provide fresh water in water-scarce areas around the world and for industrial treatment of contaminated wastewater. It can also be a great solution for getting clean water at home when conditions call for it.
Do not install a reverse osmosis filter if you do not need it, and make sure it is of high quality so that the water is safe to drink.
There are good alternatives to tap water, such as EcoPro from TAPP Water, which is easy to install, affordable and sustainable.
For general tap water and unsafe well water, ultrafiltration filters such as TAPP Waters Ultra can be a good option.