Question

WHY IS RAIN WATER HARVESTING DIFFICULT IN CITIES ??

Answer 1

Rain water harvesting is not easy in big cities. The roof area per inhabitant will be less wherever height of the houses exceeds 2 floors. Locating storage is difficult as it should be below the level of roofing gutters, the building structure will not be able to carry heavy weights on upper floors, ground-level space is less and as well as expensive.