Fibreglass water tanks can be used for other types of liquid storage besides water. As a matter of fact, they can be used on farms to store grains, fuels or even milk. Some big industries also make use of fibreglass storage tanks for storing certain kinds of chemicals and acid since they are resistant to most chemicals as well as corrosion. They are more commonly used these days than the older galvanised steel ones due to their durability and resistance to so many substances.