Adapting to climate change impacts requires a coherent social contract in which different actors agree on a clear distribution of roles and responsibilities. An urgent requirement is to understand the imagined social contracts on expected roles and responsibilities, which is particularly relevant in cities where very diverse social groups come together. However, there is limited empirical evidence on these expectations as they are often tacit and hard to capture across large populations and heterogeneous groups. Here we assess the social contract on flood risk management in Mumbai, using the concept of social listening in combination with Twitter data. We find wide gaps between and within imagined social contracts. Sentiments such as frustration and apathy expressed in tweets explain these gaps and highlight the need to build trust for achieving accepted and effective social contracts for adaptation. Theoretical, empirical, and methodological lessons can be transferred to other cities and beyond.