How does an RO water purifier work?

Your kitchen purifier pushes water so hard that it squeezes out of the salt, through a skin with no real holes. A home RO purifier chains a sediment filter, activated carbon, a booster pump, the RO membrane, a carbon polish, a UV lamp and UF fibres, a mineral cartridge and a storage tank.

Read how it works: How does an RO water purifier work? · The history of the RO water purifier · More boxes on Glassbox

Chapters in this interactive model

1. Inside an RO water purifier: Eight stages on the wall, one tiny membrane doing the hard part.
2. Osmosis, and how to reverse it: Water sneaks towards salt. Push hard enough and it goes the other way.
3. What gets through the membrane: A sheet thinner than a soap bubble, rolled up like a carpet.
4. TDS: how much is dissolved: The membrane strips almost everything; a small valve puts some back.
5. Where the rest of the water goes: For every glass you drink, two or three go down the drain.
6. UV light and UF fibres: One scrambles germs’ DNA, the other strains them out. Neither touches salt.