Water savings and reduction of costs through the use of a dual water supply system in a sports facility

•Studies confirm the potential of rainwater as an alternative water resource for saving potable water.•More than 50 % of the facility's water consumption was satisfied by non-potable water resources.•The amount of rainfall affects the degree of rainwater use.•Water saving efficiency would be higher if the storage capacity of the tanks allowed it.•The use of an alternative water resources ensured a reduction of monthly water bills to 54 %. In sustainable urban management, rainwater, greywater, and groundwater are increasingly being considered as alternative water sources where quality drinking water is not required for the water supply. Current technological solutions allow for the use of dual water supply systems in both private and public buildings. The latter, due to the potential to better manage an alternative water source in a sustainable manner, are recommended for larger scale use. In this article, the function of a dual water supply system operating in a sports facility, including the collection and use of rainwater for non-potable purposes, was evaluated on the basis of technical, quantitative and financial data. The analyses were performed to determine the facility’s water savings efficiency and cost reduction during period of 3 years. The results of the research prove that it is possible to manage rainwater for the benefit of the environment and achieve financial gain as a result of savings on charges for water from the municipal water supply and sewage disposal. While the findings of this study should encourage the use of rainwater in sports facilities, they also point to the need for properly designed of water storage tanks to maximise system efficiency.