A water tank is a container for storing water. The need for water tanks is as old as civilization. Tanks were used to provide storage of water for use in many applications, drinking water, irrigation agriculture, fire suppression, agricultural farming, both for plants and livestock, chemical manufacturing, food preparation as well as many other uses. Water tank parameters include the general design of the tank, and choice of construction materials, linings. Various materials are used for making a water tank: plastics (polyethylene, polypropylene), fiberglass, concrete, stone, steel (welded or bolted, carbon, or stainless). Earthen pots also function as water storages. Water tanks are an efficient way to help developing countries to store clean water. In the 1980s, high density polyethylene rotationally molded water tanks became popular for home water storage. Gardeners, for example, use various types of these tanks to store rain water. A Water tower, usually made of metal, is a type of elevated water tank.