1987-88: Chennai Groundwater Act comes into force. Mentions rainwater harvesting (RWH) as an alternative to groundwater extraction

1994: Notification issued making RWH mandatory for all new buildings

2001: Earlier notification modified. RWH compulsory for new as well as existing buildings when they apply for water or sewer connections

2002: Chennai Groundwater Act of 1987 amended. RWH made mandatory for all buildings