Rain water harvesting is a technique used for collecting and storing rainwater by using various means in different resources for the future use purpose (like cultivation, etc). Rain water can be collected into the natural reservoirs or artificial tanks. Another method of collection is infiltration of surface water into the subsurface aquifers before getting lost by surface overflow.

Rooftop harvesting is also a method to collect rainwater. It is of big importance to the people living in the less rainfall areas. They can continue seasonal crop harvesting using collected rain water even in the lack of regular water supply. Whenever it rains, rain water gets collected into the man made ponds or tanks.