Beschreibung Water Security is emerging as a primary sustainability challenge across the globe in the 21st century. It is a determinant for security in various societal and environ-mental aspects including food, energy, economy, environment and public health, and thus has a complex political momentum that goes far beyond the traditional water sector. In order to understand, to project, to address and to plan for water security challenges, one must collectively understand exposure to climate and environment driven hazards, as well as socio-economic determinants, and the cultural and political context, within which mankind live, work and play. Technologies (ranging from model-based scenarios and predictions to green and grey infrastructure and treatment systems, and from remote sensing to social media) and innovative financing and governance systems are proposed to address water security. This proceedings book of an International Workshop in São Paulo, Brazil will provide the reader the opportunity to acquire knowledge on Water Security considering water governance and management, technological innovation and emerging solutions for water conservation, reuse and recycle in order to achieve the Sustainable Development Goals proposed by the United Nations. More specifically, it intends to deliver essential state-of-the-art knowledge concerning - Water Security and its role in addressing the Sustainable Development Goals, - Challenges and opportunities to reach Water Security considering quality and availability, and - Water Security lessons learned and long term implications in developing countries