Sustainable Water Sources for Swimming Pools: Analysis of Regulations and Opportunities in EU Countries

Growing water scarcity across the European Union (EU) increases the need for improved water-use efficiency in water-intensive sectors such as recreational facilities. This study evaluates the feasibility of integrating alternative water sources—including rainwater, graywater, and filter backwash water—into swimming pool operations through a comparative analysis of EU legislation and selected national regulatory frameworks. The study is based on a structured desk review of scientific literature, legal documents, and technical standards published between 2010 and 2025, complemented by a qualitative SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis. Previous studies indicate that public swimming pool facilities may consume approximately 20–50 m 3 of water per day, highlighting the potential benefits of alternative water supply strategies. However, regulatory fragmentation and the absence of harmonized EU-level quality standards for recreational water reuse remain the main barriers to wider implementation. While Regulation (EU) 2020/741 establishes minimum requirements for reclaimed water reuse in agricultural irrigation, no dedicated framework exists for swimming pool facilities. Among the analyzed options, rainwater harvesting and graywater reuse appear to be the most feasible solutions. Clearer regulatory guidance and risk-management procedures could support the safe adoption of alternative water sources and contribute to improving water-use efficiency in the recreational sector.