Experiences and sustainability aspects of rainwater harvesting systems in Scandinavia

ABSTRACT In response to growing concerns over water scarcity and climate impacts in northern Europe, this study evaluates the performance and sustainability of rainwater harvesting (RWH) systems for non-potable use in Scandinavia. This study examined nine RWH systems for non-potable purposes across Denmark, Sweden, and Norway, ranging from small pilot installations to large urban developments. Semi-structured interviews were conducted with operators of nine systems. Generally, simpler systems with minimal treatment achieved better reliability, lower energy use, and higher user satisfaction than complex installations. Challenges for RWH systems included limited experience with the systems, under-dimensioned storage, regulatory uncertainties and temperatures below zero. Generally, the owners of the systems reported high levels of contentment with the systems and the quality of the water. Motivations for installing the systems varied between regions – from groundwater protection in Denmark to sustainability certification in Sweden. Difficulties encountered mostly pertained to issues that arose from the design, such as subdimensioned storage. Overall, RWH might not be a panacea for water shortages induced by climate change in northern Europe, but can offer a viable complement to municipal water supply when designed appropriately for local climate and governance conditions.