Collection of rain water through roof catchment rain fall can be collected into a storage tank?

Answer 1

It certainly can; people in Europe have been doing it for centuries. It is usually collected in a large barrel rather than a tank - it's always called a water butt.

It is supposed to be used for watering plants during dry spells, but in hard water areas the women have long known that washing your hair in rain-water leaves it softer and shinier than water from the tap.

Some people use a downspout diverter to have option of collecting rain water whenever they want to into a container or to run it normally through a downspout drain extension.

Another way to collect rain water is by using gutters with rain chains attached instead of normal downspouts. Rain chains work best hung from gutters with a few rain chains positioned evenly along the length of guttering. There are small holes or taps made into the gutter and the rain chain hang from these taps. The rain chain can extend to the ground or empty into a basin to collect rain water. Rain chains add a decorative, visually entertaining and even relaxing touch while functioning to direct rain water into your container. Rain chains are best made of copper and allowed to weather naturally.