What is old is new again. Historically, most homes used a cistern to capture and utilize rainfall for household purposes. Rain water harvesting, like the cistern, is the next big "new" thing in the sustainable water management movement.
It is an easy and fairly inexpensive practice for urban property owners to install with the pruchase or making of a rain barrel and connecting them to downspouts. When it rains water is stored in the rain barrel for watering yards and gardens. The downside to rain barrels is that they do not manage a significant amount of runoff but they are an important way to get started in water harvesting and conservation practices.