Question: why we need rain water harvesting in india

title: Rainwater harvesting
text: Karnataka : In Bangalore , adoption of rainwater harvesting is mandatory for every owner or the occupier of a building having the site area measuring 60 ft ( 18.3 m ) X 40 ft ( 12.2 m ) and above and for newly constructed building measuring 30 ft ( 9.1 m ) X 40 ft ( 12.2 m ) and above dimensions . In this regard , Bangalore Water Supply and Sewerage Board has initiated and constructed `` Rain Water Harvesting Theme Park '' in the name of Sir M. Visvesvaraya in 1.2 acres ( 4,900 m ) of land situated at Jayanagar , Bangalore . In this park , 26 different type of rainwater harvesting models are demonstrated along with the water conservation tips . The auditorium on the first floor is set up with a `` green '' air conditioning system and will be used to arrange the meeting and showing of a video clip about the rainwater harvesting to students and general public .