The pressure under which the water is delivered by the public water supply systems or wells forces molecules of water via a partially porous membrane that leaves chemicals behind, and then they get washed out.


The pores on the membranes employed in the reverse osmosis system have a size of 0.0005 microns, just a little bigger than the size of water molecules. When water under pressure is forced through such sized pores, all the pollutants are left behind and pure water is fed to a storage tank. Water containing all the contaminants is unable to pass through this membrane and ultimately goes down to drain. 


The Stages of Filtration


A reverse osmosis system for domestic applications comes with a series of filters. The system has one filter ahead of the RO membrane. Then, it has a filter with activated carbon for filtering incoming water. The term activated-carbon implies that the carbon filter is given a chemical treatment to enhance its absorption characteristics and filtration capability. As a result, water passing through this stage gets filtered further. Water coming out of RO filter gets stored in a built-in storage tank.


Reverse osmosis systems designed for domestic use can efficiently clean the water contaminated with dissolved minerals and solids, heavy metals like lead, bacteria, chlorine, chemicals, pesticides, herbicides, viruses and other injurious industrial contaminants.