Been told or think you need a RO (Reverse Osmosis) water filter? How does RO work? Is there a better alternative? Is it healthy to drink water from a RO filter?
We clarify the basics that you need to know.
What is RO?
The technology was originally invented as a solution to
- Desalinate brackish water or sea water and/or
- Reduce very specific chemical contaminants.
RO is a process through which water pressure pushes the tap water through a semipermeable membrane that allows relatively small water molecules, but not larger molecules such as dissolved minerals (e.g. Salt) to pass through.
What does RO filters remove?
RO systems remove pollutants from water including nitrates, sulfates, fluoride, arsenic and much more. But it also removes healthy minerals such as magnesium, calcium, potassium and sodium.
Generally claims around what RO removes is based on high pressure industrial RO filters so therefore lower cost housefilters are not as effective.
It does not remove chlorine or soften the water and therefore activated carbon filters are almost always required in combination of RO. The activated carbon also helps remove 70+ other contaminants such as pesticides and bacteria.
“The sales guy used a TDS tester to justify the need for a RO system”
TDS measures the amount of dissolved substances in the water but this is not a good measurement of safety. Read more about TDS as a water quality measure.
Do I need a RO filter to get clean drinking water at home?
Over the past 10-15 years RO systems combined with activated carbon have been marketed as the only solution for household drinking water. In reality RO filters are a waste of money and water for most households.
Before purchasing an RO unit or any other water treatment equipment check the quality of your local tap water and what is required to make it safe and tasty.
What are the disadvantages of RO?
- Wastes as much as 6x the amount of clean water produced
- Requires proper maintenance to ensure effectiveness and safety
- Filters usually need to be replaced once every 1-3 months
- Removes healthy minerals
- Relatively expensive starting from $300 + maintenance and replacements
- Risk of bacteria growing in the water after the filter since the chlorine has been removed
Is demineralized water produced by reverse osmosis good for you?
No, it’s actually not. According to the World Health Organization, low (TDS) water produced by reverse osmosis or distillation is not suitable for long term human consumption and in fact, can create negative health effects to those consuming it. This lack of minerals may also impact the taste negatively for many people. Read more about minerals in tap water.
What are the alternatives?
Most of the tap water in e.g. Europe and North America is already potable (drinkable according to strict WHO standard). Therefore the first priority is usually improving taste and reducing risk of possible contaminants such as THMs and heavy metals. A high quality activated carbon filter will take care of this with the added advantages
- can easily be installed and replaced by anyone
- cost considerably less
- doesn’t remove the healthy minerals from the water
- don’t waste any water
- lower risk of water going stale
Examples activated carbon filters include TAPP.
There are also other alterntives such as Ion Exchange, UV purifier, Ozone and distillation. Read more in this water filter guide.
Reverse Osmosis is an amazing technology innovation providing fresh water from sea water in areas around the world where water is a scarcity and for industrial cleaning of contaminated waste water. It can also be a good solution for clean household water when the conditions require. However, in most cases the municipal water is safe to drink and a quality activated carbon faucet filter will provide fresh and tasty tap water at a lower cost and with less waste.
Contact us if you have comments/questions.