Rain water harvesting is a technique of capturing and storing of rainwater for further utilization .Its objectives are to meet the increasing demands of water, to raise water table by recharging the ground water, to reduce the ground water contamination from the intrusion of saline water, to reduce the surface run off loss, to reduce storm water run off and soil erosion, to increase hydrostatic pressure to stop land subsidence and to minimize water crisis and water conflicts. Rain water harvesting involves collecting water that fall son the roof of the house during rain and conveying it through PVCore Aluminium pipe to a nearby covered storage unit. The rain water yield varies with the size and texure of the catchment area. Before adapting rain water harvesting method, the soil characteristics ,topography, rain fall pattern and climatic conditions should be understood. The most common method is rooftop rain water harvesting. It is the low cost and effective technique for urban houses and buildings.The rainwater is diverted into the surface tanks or recharge pits where the base is filled with stones and sand , which serves as a sand filter. The advantages are reduction in the use of current for pumping water, . Increasing ground water levels, minimizing the soil erosion and flood hazards. Thus it helps to upgrade social and environmental status assuring water to the future generation.