Abstract Today, many scholars agree that changes in water availability triggered by population growth, economic development and climate change impact will increase competition between water users, making conflict more likely, especially in those countries that lack the financial, technical and governance capacities to address water-related challenge and/or in river basin riparian states that share common water resources. As early as 2012, the US Office of the Director of National Intelligence (ODNI), analysing the water issue at a regional and global level, concluded that, while water-related state-on-state conflict is unlikely to occur during the next ten years, the problem is projected to get worse in the near future. Starting from the historical reconstruction and the geopolitical repercussions of the water dispute in the Nile River Basin and focusing on the case of the Grand Ethiopian Renaissance Dam (GERD), this article aims to analyse the political, socio-economic and environmental changes that are affecting upstream countries and to detect how these new dynamics are challenging both the balance of power and the ongoing cooperation process in the region.