Section 14(2)(c) in The Chennai Metropolitan Area Groundwater (Regulation) Act, 1987
(c)the owner or occupier of any building in existence on the date of commencement of the Chennai Metropolitan Area Groundwater (Regulation) Amendment Act, 2002 (Tamil Nadu Act 37 of 2002) shall provide rainwater harvesting structures in such buildings in such manner and within such period as may be prescribed;