In several regions around the world, water- related problems are relevant and new solu- tions for a sustainable development are sought. The aim of the International Water Research Alliance Saxony (IWAS) is to de- velop system solutions to specific prob- lems using an Integrated Water Resources Management (IWRM) approach in five model regions around the world: Eastern Europe, the Middle East, Central and Southeast Asia, and Latin America. This paper presents the project objectives and challenges in one model region (Southeast Asia) with a focus on the development of sustainable waste- water management in an emerging district of the Vietnamese capital city of Hanoi.