Between 2009 and 2013, the EAU&3E research program gathered several French research teams and water utilities, with the aim to provide a scientific answer to the following question: are our water services sustainable, even in the heart of Europe? The goal of this project was develop knowledge and improve methods to achieve a sustainable management for water services. Our ambition was to go beyond the separate analysis of each dimension of sustainable development (economic, social, environmental): in parallel and together, we tried to add knowledge on 4 major dimensions (namely: environment, economics, equity and governance), applied to a set of empirical case studies in France and in other OECD countries. We specifically focused on: a) the recent decline in water consumption and its feedbacks with water tariffs and water utilities' financial balance; b) the long term asset management issue, related to the necessary renewal of aging water infrastructures; c) the redistributive effects, including growing water poverty due to counter-intuitive effects of water tariffs; d) the new territorial scaling options for water service management (up-scaling, downscaling, technology mix), including multi-level governance to improve the resilience of urban water supply and to foster the participation of water users. Lastly, we synthesized our findings in a set of scenarios on upcoming possibilities for future water service management in European cities. Forecasting offers many interesting tools to support water services authorities and operating companies in its decisions and to better apprehend the sustainable/unsustainable paths for its future. In this paper we focus on large cities in France (Paris) and Spain (Madrid and Barcelona).