There is no life without water. Water is a driver for development: it is vital for human nutrition and health and essential for ecosystem management, agriculture, energy, economic development, peace, and security. Yet, billions of people around the world are continuing to suffer from poor access to water, sanitation, and hygiene. Some 2.2 billion people around the world lack access to safely managed drinking water services, 4.2 billion people do not have access to safely managed sanitation services, and 3 billion lack basic handwashing facilities. Many societies are further confronted with increasing water scarcity, lowering water quality and the indirect impacts of climate changes on water system functions and services. In addition, in many regions of the world, governance and institutions and financial resources dedicated to water management are insufficient for reaching a sustainable trajectory for water management. The current challenges related to water are therefore multi-dimensional, multi-scale and complex, and intertwined with the many other challenges of the sustainable development agenda. Addressing these complex challenges needs multi- and interdisciplinary approaches, and expertise from different scientific disciplines. This should be grounded on a thorough understanding of the water system, the water system processes and associated water services and functions. The Circle U. is a recently created European university alliance that aims constructing, by 2025 an inclusive, research-intensive and interdisciplinary European university. Students, staff and partners from civil society, businesses and the public sector will collaborate to jointly develop competencies and solutions for keeping Europe and the planet healthy, peaceful, democratic and prosperous. Louvain4water is a transdisciplinary consortium that develops basic and applied research, advanced training and services in the field of water at UCLouvain. The expertise available in the Circle U. alliance, or in local platforms of participating ...