How to maintain your Reverse Osmosis filter system:

Cathal Walsh
Environmental Blogger
Wednesday, 15th May 2019
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Water dripping from a tap into a glass

Reverse osmosis is a filter system widely used in many homes as well as in commercial settings. Reverse osmosis filter work based on the osmosis principle. This principle states that when a semipermeable membrane separates two fluid spaces, water will flow from an area of lower solute concentration to one of higher solute concentration to achieve equilibrium so that the osmotic pressures are balanced.

In the case of reverse osmosis however the osmotic pressure is reversed (as the name entails) and is used to push the water through a semi permeable membrane.  This membrane separates out the dissolved particles in the water and only allows pure water to pass through the filtration system.

Most of the more simple RO systems have 4 stages, and when maintaining them one should be mindful of each stage.

The first stage is a pre filter stage. This stage prevents dirt and sand from getting further into the system. Due to the nature of its purpose it can easily become clogged and stop working if not maintained, it should be replaced every 6 to 9 months.

The second stage is a carbon filter designed to filter out chlorine and any other taste or odour contaminants. This should also be replaced every 6 to 9 months.

The third stage is the actual RO membrane which carries out the osmosis.  These membranes should be replaced every 2-3 years.

The fourth stage is a carbon filter which ‘polishes off’ the filtered water to remove any remaining taste or odour Impurities in the water. This should again be replaced every 6-9 months.

It is also recommended that you clean your RO system once annually. This is done by removing all the filters and letting the water drain out of the RO system. Then you flush it out with hydrogen peroxide and let the system run for at least two cycles before setting it back up again.

If you have any doubt that your RO system may not be working, get the water coming from it tested at


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