This study develops a model of water extraction using endogenous social norms. Many users are connected by a unique shared resource that can become scarce in the case of over-exploitation. Preferences of individuals are guided by their extraction values and their taste for conformity to social norms which provide incentives to follow others. As the main result of this study, the uniqueness of the Nash equilibrium is established under a sufficient condition. Subsequently, some comparative statics analysis shows the effects of changes in individual heterogeneous parameters, conformism, and network density on the global quantity extracted. Welfare and social optimum properties are established to avoid the tragedy of the commons and suboptimal consumption of water. Finally, this theoretical framework is completed by extensions to discuss anticonformist behaviours, levers of water preservation, and awareness of consumers.