Our KARNATAKA in mysore district, 20 houses collected 10000 l by rooftop harvesting

The state of Tamil Nadu in India has made rooftop rainwater harvesting structures in homes compulsory. This initiative was introduced to address the growing water scarcity issue and promote sustainable water management practices.









Tamil Nadu is located in the southern part of India and experiences a predominantly hot and dry climate. The state faces acute water scarcity, especially during the summer months when the demand for water exceeds the available supply. To combat this issue, the government of Tamil Nadu implemented a policy mandating rooftop rainwater harvesting structures in all buildings across the state.









1. Legislation: The Tamil Nadu government passed the Tamil Nadu Groundwater (Development and Management) Act in 2003, which made it mandatory for all buildings with a roof area of 100 square meters or more to have a rainwater harvesting structure. This legislation also extended to existing buildings that were constructed prior to the implementation of the law.

2. Design and Construction: The rainwater harvesting structure comprises a collection system installed on the rooftop, which diverts rainwater into storage tanks or recharge pits. The system typically includes gutters, pipes, filters, and storage facilities. The design and construction of these structures need to adhere to specific guidelines provided by the government.

3. Inspection and Certification: The government authorities carry out regular inspections to ensure compliance with the rainwater harvesting regulations. Once the structure is deemed satisfactory, a certification is issued to the building owner, indicating their compliance with the law.









1. Water Conservation: Rooftop rainwater harvesting helps conserve water by capturing and storing rainwater, which can be used for various purposes such as gardening, cleaning, and flushing toilets. This reduces the dependency on groundwater and other unsustainable water sources.

2. Recharging Groundwater: The collected rainwater can be directed into recharge pits or wells, replenishing the underground water table. This aids in maintaining the overall groundwater levels, especially during periods of low rainfall.

3. Mitigating Floods: By collecting rainwater from rooftops, the load on stormwater drains is reduced, thereby minimizing the risk of urban flooding during heavy rainfall events.

4. Cost Savings: Implementing rooftop rainwater harvesting can lead to significant cost savings for households and communities by reducing their reliance on water supplied by external sources.









The compulsory implementation of rooftop rainwater harvesting structures in Tamil Nadu has been a significant step towards water conservation and management. By making it a legal requirement, the government has ensured widespread adoption of this sustainable practice. This initiative has not only helped in addressing the water scarcity issue but also promoted a sense of responsibility among individuals and communities towards water conservation.