In the current situation of global warming, the availability of fresh water is a blessing. Due to the uncontrolled extraction of groundwater, the water table is decreasing at a rapid pace. This reduction and water scarcity dilemma could be resolved through better management of available water resources. Rainwater harvesting is the most applicable and demanding way for the conservation of water, which includes localized storage of rainwater for different future uses. In this paper, a case study of Capital University of Science and Technology (CUST) Islamabad Pakistan has been taken to assess the rainwater harvesting potential. Google Earth Pro (GEP) was used for marking out the boundaries of the study area. Digitization of the campus was worked out by using ArcGIS. The overall demand for water in the CUST was calculated by considering the total population. The selection of suitable sites for the storage of rainwater harvesting (RWH) was identified. Quantity of rainwater ware calculated by using rational method. Storage tank size and location were suggested in three different places based on the natural ground slope. The result of this study shows that 100% of the water will be saved by rainwater harvesting. This saved water can be used for other purposes like landscape irrigation. This will help in decreasing the usage of groundwater resources.