Roof top water harvesting is important in Rajasthan because: (i) It was commonly practised to store drinking water. (ii) The rainwater can be stored in the tanks till the next rainfall, making it an extremely reliable source of drinking water when all other sources are dried up, particularly in the summers. (iii) Rain water, or palar pani, as commonly referred to in these parts, is considered the purest form of natural water. (iv) Many houses construct underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool. (v) Some houses still maintain the tanks since they do not like the taste of tap water.