Water is considered the gold of the 21st Century. It is a distinctive feature of our planet, allowing life to flourish. Freshwater is a limited resource and is unevenly distributed in space and time. Freshwater resources are under intensifying pressure to meet social, economic and environmental needs of a growing world population. We are in a crucial moment, and the direction we take will determine the livelihood of future generations. Coping with climate change by increasing local resilience and adaptation strategies are key elements towards water security. Cooperation among actors and close collaboration between science and policy are paramount for satisfying human needs and achieving sustainable development. The article provides an overview of the challenges society is  facing with respect to water security in a changing environment.