Rapid urbanization and industrialization had increased the demand for fresh water and thus depleting substantially the ground water table. Secondary sources like rivers, lakes are either vanishing or contaminated. It is said that by 2050, 7 billion people in 60 countries may face water scarcity. Climate change is expected to contribute 20 per cent of the increasing scarcity globally. Due to the poor storage facilities in the catchment regions & wastage of rain water being allowed to flow into sea add to the problems. Under these circumstances, Rain Water Harvesting alone can revive the hope of recharging the ground water to maintain the sustenance of the planet. Rainwater Harvesting Systems include collection and storage of rain water for different needs. The collected rainwater is stored & is used subsequently to suit the domestic, agricultural, industrial applications. Further, these systems are also applied for recharging ground water. Rainwater harvesting is also used for Managing the ground water & for preventing evaporation & seepage.