The BMC clears building proposals only after the buildings have facilities for this (rainwater harvesting) technique. Otherwise, the occupational certificate (OC) is not given to the builder. However, many a times builders show the plan on paper but never implement it. According to a senior official in the Developmental Plan Department of the BMC, there is no monitoring body within the BMC to ensure that every private co-operative housing society invests in rain water harvesting.