Assessing rainwater harvesting scenarios to mitigate potable water storage needs in Algerian individual houses under intermittent supply.

Urban areas in Algeria are increasingly suffering from water scarcity due to climate change and rapid urbanization, prompting the government to introduce an intermittent water supply system. This situation requires households to store potable water during supply interruptions. This study investigates the potential of rainwater harvesting (RWH) to reduce the need for such storage in single-family homes in the municipality of Beni-Mared (north of Algeria). Through five simulated scenarios: "Current" which represents the existing situation without RWH; "Maximum" in which all available rainwater is captured; "Switch" in which the existing potable water storage tanks are used for rainwater; "Optimal" in which the size of the storage tanks and efficiency are balanced; and "Outdoor" in which the focus is on rainwater for external purposes such as watering. The results show that the "Maximum" scenario has the greatest potential, as it reduces the need for potable water storage by up to 84.5%, although it requires large and potentially expensive tanks. The "Optimal" scenario offered a practical solution in which a 2.7 m³ tank covers up to 33% of the storage. The "Switch" scenario, where existing tanks were repurposed, reduced storage requirements by 15.07%, while the "Outdoor" scenario, designed for external uses, achieved a more modest reduction of 5.85%-6.71%. These results demonstrate the importance of implementing an adapted RWH approach supported by a comprehensive development strategy, community involvement and financial support to effectively address water scarcity in Algeria.