Rooftop Rainwater Harvesting at Home: A Monsoon-Ready How-To

Harvest potential (litres) = roof area in m² × annual rainfall in mm × ~0.8; 1mm of rain on 1 m² gives 1 litre

Decide first: store the water in a tank to use, or recharge it into the ground to revive your borewell/water table

A first-flush diverter that dumps the dirty opening rain is the single most important cleanliness fix

Basic recharge setups can start under ₹20,000–30,000; storage with big tanks costs more

Many states and city byelaws already make rooftop harvesting mandatory above a plot-size threshold