National Capital Territory (NCT) of Delhi occupies an area of 1483 sq. km. The total population of NCT Delhi, as per the census 2011 is 167.53 lakhs. The total water requirement for drinking and domestic purposes works out to be 927 MGD. The Delhi Jal Board (DJB) supplies 815 MGD (including around 100 MGD from groundwater). The deficit in drinking water supply works out to be 112 MGD. The groundwater resources of the district though overexploited, it can partially meet the deficit in the drinking water supply. The normal annual rainfall of NCT Delhi is 611.8 mm. About 81% of the annual rainfall is received during the monsoon months July, August and September. The rest of the annual rainfall is received in the form of winter rain. The depth to water level recorded in NCT Delhi during May 2015 ranges from 1.20 to 62.22 meters below ground level (m bgl). About 50% of wells of South district show more than 40 m bgl water level and 19% of wells have 20 to 40 m bgl water level. In New Delhi and Southwest districts, the water level in the range of 10 to 20 m bgl is shown by 57% and 35% wells respectively. When surface water such as rivers and lakes are inadequate to meet our demand then we must depend on groundwater. Due to rapid urbanization and Deforestation recharging of groundwater has diminished. Excessive tapping of groundwater, through numerous boreholes, has led to a decline in the water table. In order to increase food production, we need more and more water for irrigation Thus, there is an urgent need for conservation of water. The augmentation of groundwater by rainwater harvesting is the need of the hour. Rainwater harvesting is the collection and storage of rainwater that runs off from roof tops, parks, roads, open grounds, etc. This water should be either stored or recharged into the groundwater.