Water and energy are inextricably linked in today's society. This paper broadly introduces the water–energy nexus before focusing on sub-Saharan Africa, where residents have the poorest access to both clean drinking water and electricity worldwide. Given that many of the affected people live in remote areas, new solutions are required to improve the quality of life. The potential of decentralized photovoltaic-powered membrane filtration systems for the provision of potable water is highlighted. In particular, the potential of this technology is investigated for the removal of dissolved trace contaminants such as fluoride, which naturally occurs at extremely high concentrations in the water sources of northern Tanzania. Results from field research demonstrate the importance of matching the best membrane to a particular water source to achieve the highest permeate production that complies with drinking-water guidelines at the lowest specific energy consumption.