The spread of soy monoculture in the Brazilian Cerrado relies on land and water grabbing, although water appropriation is a least studied issue in the current literature. A mixed-methods approach was used to study changes in water use in western Bahia and the evolution of water and environmental standards over the last 20 years. The results show that the deregulation of environmental laws by the Bahia state Institute for the Environment and Water Resources (Instituto do Meio Ambiente e Recursos Hidricos, INEMA) has facilitated deforestation and water grabbing for large-scale irrigation by industrial agriculture. The social dynamics of struggles and resistance to this process was also analysed. The results show that water appropriation in the neoliberal agricultural frontiers of the Cerrado has changed not only water use and flows but also water governance systems, flows of power, and the representations that underpin them.