Plain, sloping roofs can collect up to 50% more rainwater than flat roofs with gravel. The water collected from sloping roofs is of a higher quality than collected from other surfaces.
According to researchers, these statistics lend support to calls for rainwater collection infrastructure to be integrated into urban planning.
Collected water can be used to water streets and gardens, wash floors or vehicles and fill cisterns.
Read more at FEYCT - Spanish Foundation for Science and Technology