Climate change-related drought risks are intensifying in many urban areas, making stakes particularly high in contexts of severe vulnerability. Yet, how social power, differential agency and economic visions will shape societal responses to droughts remains poorly understood. Here, we build a social-environmental scenario of the possible impacts of an unprecedented drought in Maputo, which epitomizes a Southern African city with highly uneven development and differential vulnerability across urban areas. To build the scenario, we draw on theoretical insights from critical social sciences and take Cape Town (2015–2017) as a case-in-point of a locally unprecedented drought in Southern Africa. We show that future droughts in Southern Africa will probably polarize urban inequalities, generate localized public health crises and regress progress in water access. Climate policies must address these inequalities and develop equitable water distribution and conservation measures to ensure sustainable and inclusive adaptation to future droughts.