Potential for potable water savings using rainwater: a case study in a university building in Southern Brazil

The purpose of this study was to evaluate the potential for potable water savings and the financial viability of a rainwater harvesting system in a private university building located in southern Brazil. The water end-uses were estimated based on answers about frequency and time of use of the water appliances. The rainwater tank and the financial viability analysis were assessed using the Netuno computer programme. The per capita water consumption was 5.38 L/person/day and the highest water end-use was observed for toilet flushing (51.9%). The potential for potable water savings ranged from 49.7% to 72.4%. The cost to implement the system was estimated at USD 25,730.78 and the payback period ranged from 8 to 9 years. The main conclusion is that rainwater harvesting in private university buildings in Brazil can be economically feasible even when the per capita water consumption is low, as total water consumption tends to be high.