There are a variety of applications in which submersible pumps can be used. Single stage submersible pumps are often used in sewage pumping, industrial pumping and heavy duty drainage. In addition, they can be used in tandem with the filters found in aquariums and ponds. There are also multiple stage submersible pumps and these tend to be used for the abstraction of water inconjunction with borehole drilling or water wells. The whole pump is submerged in the liquid helping to prevent pump cavitation which is caused when the pump and liquid are on different levels. Submersible Pumps cover small and mediumsized applications with pump discharge sizes ranging up to 12`.