Unlike to fossil fuels, water is an irreplaceable basic resource. In times of depleting fresh water resources highly effective water management concepts become more and more unavoidable. The industry has realised that: Wastewater partial-stream separation and recycling is spreading there increasingly since many years. In this paper this concept is realised the first time in domestic water management and the current state of research is presented. With two water loops (black water and grey water) the water consumption of domestic and functional buildings (hotels, hospitals, etc.) can be reduced significantly: Additionally, these buildings are physically waste water free, all valuables (compost, mineral fertilizer and energy) are recovered mainly mono-fractioned, and finally all micro-pollutants (hormones, pharmaceuticals) are mineralised completely.
