In a state-of-the-art reverse osmosis filter system, salts are separated from tap water to make it drinkable. The membrane, which is more like cellophane, allows only water to pass through. The filtration process used by commercial systems is similar to that used by classic residential reverse osmosis water filter systems. Reverse osmosis technology purifies water and removes salts, minerals and other impurities. It also discards harmful bacteria, protein, and other particles that have a molecular mass. These reverse osmosis water filter systems clean the water of contaminants and remove non essential and corrosive salts, metals, chemicals that are found present in the water.