Towards Sustainable Urban Water Management: A Case Study on Rainwater Harvesting in Romania

Urban areas in Europe are increasingly challenged by water scarcity, climate variability, and pressure on municipal water systems. Rainwater harvesting (RWH) offers a decentralized, sustainable solution to reduce dependence on potable water, mitigate stormwater runoff, and support urban water resilience. This study presents a case study from Cluj-Napoca, Romania, where an RWH, storage, and on-site retention system was implemented in an educational building. Rainwater was analyzed for key physico-chemical parameters to assess its quality for non-potable applications. The results show that the system significantly decreases municipal water demand for irrigation and cleaning, while seasonal precipitation variability strongly influences storage efficiency. Most water quality parameters fall within acceptable ranges for non-potable uses, although pH and mineral content indicate that additional treatment is required for potable applications. The findings demonstrate the potential of decentralized RWH systems to enhance sustainable urban water management, reduce hydraulic stress on sewer networks, and provide economic benefits through avoided discharge costs.