A water tower is a facility whose purpose is to achieve the correct water pressure in the water supply system by connecting it to water stored at a high altitude (in the water tower). Modern Swedish water towers are often sponge-shaped after "Svampen" (the sponge) in Örebro from 1958.
The water towers used to be built of masonry. Later, the towers were usually made of masonry in combination with a skeleton of reinforced concrete, exclusively of concrete or masonry, or a lattice of wrought iron was used.
Many water towers have characteristic appearances and act as landmarks. Since they often dominate the image of the buildings they are part of, it is important that they are well designed also from an aesthetic point of view.
In the USA the water towers in smaller cities are usually marked with the name of the city, which is appreciated by amateur pilots, as it simplifies navigation.
Water towers have been used by railways with the help of Water cranes to fill water in Steam locomotives.