The demand for water among various sectors is increasing due to economic development and population growth which creates competition within different sectors. The water and food security of the country will have a direct impact in the future due to the demand for water. Rainwater harvesting is an effective technique in high-water demand regions. The study’s primary goal is to estimate the amount of rainwater that can be harvested in the TCE campus, Madurai through rooftop rainwater harvesting. The applications such as Google Earth Pro and ArcGIS were used to calculate the rooftop area and quantity of water that can be harvested. A total roof area of the campus consists of 33,276 m2 which can harvest a total volume of 21,638 m3 of water. This harvesting water meets 26% of water demand in the campus. Water audit is one of the emerging methods for conserving water and increasing accountability for water utility systems.