An angle valve is fitted to the water supply in your home from a cold water line and a tube directs the cold water to the RO system. The first stage of the RO system is a pre-filter that removes the solid materials like silt, rust, and dirt from the water. This first stage prevents the other RO filters from becoming clogged with larger debris. The second and third stages are where the true reverse osmosis begins. The reverse osmosis membrane and carbon filters make up these stages. These filters remove chlorine from the water. By having 2 stages, the system removes the chlorine much more effectively. By this time, the water is clear and tastes pure. Apart from chlorine, there are many other chemicals that can affect our health and the taste of the water. This include fluoride, lead, and chromium. During the fourth stage, membranes remove these other elements from the water. The final stage of a 5 stage reverse osmosis filtration system is called post-filtration. As the water leaves the tank, on its way to the faucet, it passes through a filtration membrane that collects any particles that may have accumulated inside the tank. Some 5 stage RO systems use a process known as remineralization which replaces essential minerals that are removed during the previous stages. These essential minerals help provide the body with the necessary electrolytes and elements for clean and healthy drinking water.