"Reverse osmosis" – at first it sounds like complicated physics from school. But the principle behind it is actually quite simple to understand. In this article, we explain what reverse osmosis is, how it works and why it is such an effective water filtration technology.
What Does Osmosis Mean?
To understand reverse osmosis, it helps to start briefly with regular osmosis.
Osmosis is a natural process: when two liquids with different concentrations are separated by a thin membrane, water automatically moves from the cleaner side to the more contaminated side – until the concentration equalises. Nature has known this process for millions of years – it takes place in our body cells, for example.
So What Is Reverse Osmosis?
Reverse osmosis – also known as RO – simply reverses this natural process.
Instead of letting water move through the membrane on its own, it is forced through under pressure – from the contaminated side to the clean side. The membrane is so fine that only tiny water molecules can pass through. Everything else – limestone, chlorine, heavy metals, bacteria, viruses, microplastics – remains on the other side and is discharged as wastewater.
The result: almost pure water at the touch of a button.
How Does a Reverse Osmosis System Work at Home?
A reverse osmosis system for the home works in three steps:
Step 1 – Pre-filter The tap water first passes through a pre-filter. This removes larger particles, sediment, chlorine and unpleasant odours – while also protecting the sensitive membrane.
Step 2 – The Membrane The heart of the system. The water is forced through the ultra-thin reverse osmosis membrane under pressure. The membrane has pores of only 0.0001 micrometres – that's about 500,000 times smaller than a human hair. Limestone, heavy metals, bacteria, viruses and microplastics have no chance of getting through.
Step 3 – Post-filter In the final step, a post-filter further refines the already purified water – for a fresh, clean taste.
The purified water is stored in a tank and is available at the touch of a button at any time.
What Exactly Does Reverse Osmosis Remove?
A high-quality reverse osmosis system removes up to 99% of all dissolved contaminants from tap water. These include:
- Limestone – particularly relevant in Cyprus with very hard water
- Chlorine and chloramines – for better taste and smell
- Heavy metals – such as lead, copper and mercury
- Bacteria and viruses – for maximum safety
- Microplastics – a growing problem in many water supplies
- Nitrates and pesticides – residues from agriculture and industry
Why Is Reverse Osmosis Better Than Other Filter Types?
There are many types of water filters – activated carbon filters, ceramic filters, UV filters. Each has its strengths. The key difference with reverse osmosis: it filters at the molecular level.
Simple activated carbon filters mainly improve taste and smell – but they don't reliably remove limestone, heavy metals or bacteria. A reverse osmosis membrane, on the other hand, retains almost all dissolved substances – no other household filtration method achieves this.
Is Reverse Osmosis Water Healthy?
This is a frequently asked question. Since reverse osmosis also removes some of the natural minerals from the water, many people wonder whether it's healthy.
The answer: yes, reverse osmosis water is safe and healthy to drink. The vast majority of our daily mineral intake comes from food – not from water. The advantage of high purity far outweighs this.
Reverse Osmosis in Cyprus – Why It Makes Particular Sense Here
Cyprus has some of the hardest tap water in the EU. Around 70% of drinking water comes from seawater desalination – a process that also uses reverse osmosis. The water is safe, but often has a slightly salty aftertaste and high limestone content.
For households in Cyprus, having your own reverse osmosis system is therefore not a luxury – it's a practical and long-term cost-effective solution for enjoying clean, fresh-tasting water every day.
If you'd like to find out more about our Coway reverse osmosis systems for Cyprus, feel free to browse our product range at hydrateme.cy – or contact us directly at support@hydrateme.cy.
Have questions about the technology or want to know which system suits your household? We're happy to advise you free of charge: +357 97 762834