Subhadrika Sen
Collect rainwater from the rooftop in large barrels and use them to wash the house, for gardening, etc.
Create a rooftop garden so that the rainwater directly waters the plants. But be sure to have a proper drainage, else it might cause flooding.
Build your pavements with porous materials which help water seep into the ground and keep it cool, even on hot days.
Underground collection of rainwater helps not just a house but a community at large.