Why Does an RO System Have Five or More Stages in the Filtration Process? What is the Purpose of Each Step?

Q6 Why Does an RO System Have Five or More Stages in the Filtration Process? What is the Purpose of Each Step?

The first filter is a 5-micron particle filter to remove dirt, rust, and other sediment.

The second filter is a carbon filter which removes organic chemicals, and most importantly, removes any chlorine from the water which can react with the RO membrane and damage it.

Third is a fine, 1-micron filter which further removes finer particles remaining after the carbon filter.

Fourth, the RO membrane, the heart of the system, will filter 95-99% of the dissolved contaminants from the water. The contaminants are washed down the drain, and pure water flows into a pressurized storage tank.

Fifth, after the storage tank and before the faucet, is another carbon filter to “polish” the water, removing any remaining odors or tastes.

If desired a remineralizing filter can be added as a sixth stage, or used in combination with the fifth stage carbon filter as a combination (fifth stage) “polishing-remineralizing” filter.