Water is the most valuable resource which is available on the earth’s surface, covering 2/3rd part of the total earth’s surface. Human requires water for a variety of tasks in our daily lives, so life would not exist without it. As the world population is increasing day by day, the demand increases for quality drinking water. In a growing country like India, Nepal having scarcity of water sources, became a major problem due to the increase in the consumption of water. Besides this many coastal parts of Nepal and India are challenged by floods due to heavy rainfall during the monsoon season. Due to the increasing population, weather change, variation of rainfall within the country, and sudden disparity of metrological parameters like humidity, the surface, and sub-surface resources are constantly depleting in many countries. Hence its proper management could reduce problems due to shortage of water and food crises. So rainwater harvesting has proven to be one of the most cost-effective and environmentally friendly methods to overcome this problem, conserve the water for future use, and recharge groundwater. The RWH technique is used to resolve the problem of water scarcity problems during the non-monsoon season by storing 129.5m^3 in a year on the rooftop of the house. This initiative helps to utilize the water supply for household purposes, and agriculture and also will help in the recharge of the groundwater. There is greater chance that the rainwater might be contaminated by dust, floating substance, bacteria, and hazardous Chemicals that require treatment before usage. We have used slow sand filtration and solar technology methods to reduce pollution. This study aimed at designing a rooftop rainwater harvesting structure for a rural house in Dhangadhi Nepal. The roof of the house was chosen as the required catchment area for rainwater harvesting taking into the consideration of the water demand for household purposes. The necessary data such as catchment regions and average precipitation are gathered. In this paper selection of good rooftop materials, basic rooftop designing for rainwater harvesting, basic cost analysis, and solar power pump for lifting the water for future use have been done.

Keywords : Rooftop Rainwater Harvesting, Water Scarcity, Dhangadhi Nepal, Catchment, Cost Analysis, Solar Power Pump