Why standard home reverse osmosis systems often disappoint

Reverse osmosis is the most effective water filtration technology available for drinking water. It removes what activated carbon filters and filter jugs simply can't touch: heavy metals, nitrates, pesticides, PFAS, pharmaceutical residues, microplastics. On that point, there's no debate.

Where it gets complicated is the installation. A standard domestic reverse osmosis system means three to five filter housings, a membrane, a pressurised storage tank of 8 to 12 litres, a pump, and an electrical connection. Under a standard kitchen sink, there's not much room left for anything else. And if you're renting, the question of drilling into the sink or worktop for a dedicated tap can stop the whole project before it starts.

Then there's the tank. The filtered water sits in a pressurised vessel waiting to be used — sometimes for several days. Not dangerous, but not ideal either for water you've specifically chosen for its purity.

The OneZero French Eaux eliminates all three of those constraints.

An under-sink water filter built differently

The OneZero connects directly to the cold water supply under the sink and to a dedicated tap. It needs no electrical connection of any kind: mains water pressure alone drives the reverse osmosis membrane and produces purified water — the same technology as standard systems, without the pump and without the tank.

The result is filtered water produced on demand, fresh with every draw. No storage, no water sitting in a vessel. Its compact footprint (360 × 360 × 150 mm, 8.2 kg) means it fits easily where a traditional system with a tank simply wouldn't.

Its high-performance membrane reduces up to 99.9% of contaminants found in tap water: bacteria, viruses, chlorine, heavy metals, microplastics, nitrates, pesticides and pharmaceutical residues. What comes out of your tap is water of a purity comparable to the best bottled water — produced at home, with zero plastic waste.

And because it uses no electricity, it can also be installed where an outlet isn't available: a holiday home, a chalet, a professional space, or simply a kitchen sink with no nearby socket.

OneZero vs standard reverse osmosis with storage tank

Technical specifications

Frequently asked questions

Do home reverse osmosis systems always need electricity?

Most domestic reverse osmosis systems require an electric pump to boost pressure or fill a storage tank. The OneZero runs on mains water pressure alone — no outlet, no wiring, no energy consumption.

Is the OneZero suitable for a rented flat or apartment?

Yes. Installation is limited to connecting to the existing cold water supply under the sink and fitting a dedicated tap. No electrical work, no structural modifications to the property.

What water pressure is needed for the OneZero to work?

A minimum of 2 bar is recommended, which is standard mains pressure in most homes across Europe. The operating range is 1.5 to 6 bar.

Is the filtered water remineralised?

Reverse osmosis water is highly pure, which means it is naturally low in minerals. For those who prefer a remineralised water, an optional remineralisation cartridge is available — it reintroduces calcium and magnesium and balances the pH for a more rounded taste.

How often does the OneZero need servicing at home?

Pre and post-filtration cartridges should be replaced every 6 to 12 months. The reverse osmosis membranes have a lifespan of 2 to 4 years depending on local tap water quality and household consumption.