What is rainwater harvesting and How do you implement them in apartment?

Rainwater harvesting system is collection of rainwater from the surface which directly receives rainfall. It can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground.

Following links helps to understand what is rainwater harvesting and how to implement them successfully in your apartment.

http://www.reddit.com/r/reddit.com/comments/avm9y/rainwater_harvesting_an_efficient_water_solution/