The project " Youth expertise for water as a common good " aims for the construction and sharing of knowledge among young people in the field of water as a common good. In Europe, water issues emerge and challenge in a complex way citizens, and especially young people. The project will build a strategic partnership between the French, Italian and Moldavian youth to enrich in the South and Eastern Europe the established network of water keepers initiated three years ago on the social economic and environmental aspects of water in the context of a sustainable development. The project will enable European young people from 3 countries ( France , Italy, Moldova), with specific policies and models of water management, to create a common knowledge base for a " model of water as a common good of XXI century ", based on their analysis and audit of national policies, pooling, trainings, discussions and exchanges. This project will lead to a strengthening of youth power by encouraging them to take action as citizens and then as professionals (or politicians) for a new water paradigm and better account of climate change. Youth can be powerful catalysts for change and provide innovative solutions to the problems of Europe in terms of policy and sustainable development by acting in their local communities. Through the actions undertaken, the youth will launch an appeal to raise the level of shared knowledge . they will work together with research actors, civil society, professionals and local communities and share their knowledge and know-how in the field of water. So will emerge at European level the principle of "citizen and public expertise of water" co-driven by scientists and citizens stakeholders. An online degree course will be available at the end of this project and will continue to strengthen citizen expertise in water as a common good at European and international levels. A more democratic governance, giving citizens a real role, is a challenge to achieve a new model of water management adapted to the needs and realities of the 21st century. This is the challenge that today's young generation will have to face. Young people participation in the International Summit of Climate in Paris with a new water paradigm to propose and defend will be the top of the advocacy strategy to build and succeed collectively.