This paper discusses the political economy of the water-energy nexus in South Africa, by using Medupi power station as case study. Medupi is a huge coal-fired plant that signals the country's attachment to coal in the face of the African National Congress' repeated commitments to a low-carbon, just transition. Although Medupi's water consumption is much lower than that of older power stations, the plant still needs massive amounts of water for its operations. For this reason, the state is building a new water infrastructure based on an inter-basin transfer scheme from the Crocodile River in Gauteng to the Mokolo River in Limpopo Province, where Medupi is located. A political economy analysis is employed here to show who is going to win and who is going to lose from this new water scheme. For instance, the rural poor living upstream of the Mokolo Dam cannot rely on the river's water to solve their own water crisis, as the Mokolo has been allocated to Medupi. The case of Medupi and its water-energy nexus, therefore, serves to illustrate a broader 'water question' in the country. This has to do with the state's politics of water allocation privileging production over social reproduction, and hence leaving the basic, material needs of the poor unmet, under the (false) assumption that economic growth will translate into better water access for all.