Rainwater harvesting is a technique of increasing the recharge of groundwater by capturing and storing rainwater. Many low cost techniques are used in semi-arid areas like Rajasthan in Bikaner, Phalodi and Barmer, underground tanks or tankas are used for storing drinking water. They are connected to the sloping roofs of the houses through a pipe. Rainwater is stored in the tankas for three to five years. Rainwater or Palar Pani is considered the purest form of fresh water.
