Resource efficiency of wastewater management is a question of optimizing at the same time the management of resources in wastewater (e.g. water), the resources spent on treatment and transport (e.g. energy), the natural resources to protect (e.g. the receiving waters), and the anthropogenic resources (e.g. capital). For instance, wastewater can be treated to any given quality, but only at the expense of energy and investment costs. Today, many up-coming problems are solved incrementally, leading to resource consuming solutions optimized for water pollution control in well off countries, whereas large parts of the world have at the best very simple wastewater treatment. From a global point of view, a system change is necessary in order to solve the immense problems arising from global population growth, urban development and climate change. Source separation is a promising concept for resource efficient wastewater management, but a more concerted effort is necessary from the international community in order to develop competitive technologies and overcome the inflexibility of the present end-of-pipe technology. Much more research and development are necessary, not only in the area of engineering, but also with respect to the socio-economic dimensions, especially in the area of regulation, suitable governance and management models, and concerning the involvement of industrial partners.