Quantitative assessment of water use efficiency in urban and domestic buildings

This paper discusses the potential of water savings at property, household and urban levels, through the application of environmentally sound technologies (ESTs), as well as their quantification using the software Wise Water. Household centered measures are identified that allow for significant reduction of drinking water consumption with comparatively small effort, and without limitation of comfort. Furthermore, a method for the estimation of water recycling, for rainwater harvesting and for the utilization potential as locally available renewable freshwater is presented. Based on this study, the average drinking water consumption in urban households of industrialized countries could be reduced by approximately one third, without significant investment costs, either within the framework of new constructions or by the remodeling of water and sanitation systems in
residential buildings. By using a secondary water quality, the drinking water demand could even be reduced by 50%. In the case of an area-wide application, the overall fresh water demand of cities and the exploitation of fresh water resources could be significantly reduced. Due to the comparability of the domestic water use of the investigated households, the findings are internationally transferable, for example to countries in Europe, Asia, and also the USA. [authors abstract]