A one-micron filter is required for complete removal, because some parasites can be as small as two microns. A single one-micron filter is likely to clog as it removes sediment and algae. As a result, home systems commonly use a series of cartridge filters, with each filter removing smaller particles. Another option is a rapid sand filter followed by two cartridge filters. These systems filter all the water entering a home.
Some people treat only the kitchen tap water for drinking.
An option in this case is to use reverse osmosis followed by ultraviolet light or a small distillation unit. Disinfection is needed because some bacteria and viruses can pass through filters. When disinfecting using constant chlorination, a small pump automatically injects a diluted chlorine solution, usually household bleach mixed with water, into the water pipe below the filter. The chlorinated water then flows into a holding tank, where the chlorine kills any organisms. This disinfects the entire home plumbing system.