What is Reverse Osmosis? As the name implies, Reverse Osmosis is the opposite to osmosis. Osmosis is the process by which water is drawn into the stem of a plant by a pressure variation between the comparatively high pressure outside of the plant and the lesser pressure within the stem. The pressure differential that causes water to be drawn up into the stem of the plant is referred to as “osmotic pressure”.

Reverse Osmosis occurs when the same osmotic pressure is used to allow water to permeate through a membrane as a result of differing pressures outside and within the membrane. In this case, the process happens because the water pressure inside the membrane is higher than the pressure outside – the reverse of normal osmosis.The pore size of the membrane is so small that the majority of impurities and totally dissolved solids are too large to pass through it. They are therefore by-passed and discharged to drain, allowing only the pure water to pass through. The best known example of reverse osmosis is the seagull. The seagull drinks salt water and rejects the salt through a membrane on the top of the beak! Reverse Osmosis membranes typically filter to .0005 of 1 micron and are therefore fine enough to remove viruses, bacteria and parasites.They also effectively remove salts, heavy metals (lead, mercury, copper and iron etc) and most heavy molecule chemicals (insecticides, pesticides etc). .0005 is about 100,000 times finer than a human hair.