Filtered water is water that has been treated with a chemical or mechanical process to remove particles and pollutants. The exact components that are removed from the water vary with the filtration process.
Activated carbon, ultraviolet lights, reverse osmosis and distillation are some of the methods used to filter water. Activated carbon is a mechanical filtering method that removes heavy metals, pesticides, parasites, radon and other chemicals. Ultraviolet lights create and enhance filtered water by killing parasites, bacteria and viruses. Reverse osmosis and distillation are more complete filtration processes that remove nearly all contaminants from water, including pathogens and heavy metals.