This type of pitcher comes with a reservoir usually found at the top that keeps the water. The reservoir is usually linked by a couple of filters or filter cartridges. Because of gravity, the water will pass within the filters, which does not require any energy. At the bottom of this pitcher is a tank that stores the filtered water.
Some pitchers utilize a carbon block or a granular activated carbon as the main filter. However, since carbon filters can only trap several impurities, it6 has to be replaced soon. Other models use ion exchange resins to remove minerals and heavy metals.