Acid mine drainage (AMD) has generated an enormous amount of media interest and public concern in the Gauteng City-Region (GCR) over the last decade. However, it has been framed as a narrow technical concern, with government action being directed towards securing the necessary engineering and processing solutions as quickly as possible to prevent decant and treat acid mine water to industrial standards. This has arguably limited the scope for full discussion and debate on the impacts of AMD, particularly for the environment, and this bears implications for how AMD has been managed in the GCR. Government’s immediate, short and long term interventions to address AMD have been set out as a straight forward solution, but over time more complex environmental concerns have emerged. Becoming more evident over the last few years is that one of the main impacts of AMD will be its effect on the overall water security in the Vaal River System (VRS) on which the GCR relies for its supply of potable water. Limits on water abstraction from the VRS, together with the increasing need to maintain the overall water quality in the system through dilution and treatment activities, means that AMD is beginning to manifest as a binding constraint on economic development and a burden on society – in particular via escalating costs for water consumers. Fiscal constraints are likely to see GCR residents and businesses pick up more and more of the costs associated with the treatment of AMD, through the format of increased municipal tariffs. With final decisions on municipal tariffs now pending, the broader yet invisible impacts of AMD loom large. This means that the debate has moved far beyond the issue of predicted decant in each of the Witwatersrand’s mining basins. Water security for the GCR, and who will carry the costs associated with the long-term treatment of AMD, have instead taken centre stage. This paper carefully updates the historical record on AMD since the publishing of a GCRO Provocation on the issue in 2010. In doing so, it argues that the way in which AMD has been governed raises a flag around how the political economy of an issue such as AMD should be understood, publicly debated and managed. In particular, it suggests that the governance of an environmental challenge such as AMD is not only about finding a technical solution. The lack of platforms to ensure well-informed public deliberation, especially over such issues as who will pay and how, must be addressed to ensure more equitable and transparent decision-making. In light of the broader mine waste legacy inherited by the GCR, and the strong likelihood of environmental contamination becoming more commonplace in the future, these concerns are not only limited to AMD. They will only grow in importance over time.