Life Cycle Assessment of a Domestic Rainwater Harvesting System: A Case Study of Poland

Protection of water resources is an urgent priority in the context of increasing freshwater scarcity. Sustainable and circular water management focuses on reducing water consumption as well as measures to recover and reuse alternative water sources. This study assesses the life cycle assessment (LCA) of a domestic rainwater harvesting (DRWH) system located in Poland. Moreover, the most significant environmental contributors and the quantification of each component’s role in the system’s overall footprint are assessed. The study used the OpenLCA tool and assumes 1 m 3 of treated water as the functional unit. Findings reveal a highly concentrated impact distribution for the components. The high-density polyethylene (HDPE) tank dominates, which represents 78.69% of total environmental impacts and leads in 18 of the 18 categories examined. Its influence is greatest in non-renewable fossil energy use, where it accounts for 92% of the impact, and in photochemical oxidant formation, with contributions exceeding 90%. The data quality assessment (DQA) of the system resulted in uncertain temporal and geographical correlation. Further Monte Carlo simulations confirmed the uncertainties regarding climate change and energy-related impact categories. The methodology aligns with ISO 14044 guidelines, providing a foundation for evidence-based environmental management decisions.