This paper focuses on the fact that the water–energy nexus remains an irrelevant issue on the energy policy agenda and on the priorities of the energy leaders in Spain. This is a striking fact given that this takes place in the most arid country in Europe, where almost two-thirds of electricity generation would have to be halted in the absence of an adequate water supply. We contend that part of the explanation may lie in the lack of official statistics and inconsistent sources of information on the water–energy nexus in Spain. To illustrate this point, we provide examples of the uneven data available for one of the most intensive freshwater users in the thermoelectric sector in Spain: nuclear power plants. Our research demonstrates the need for improved indicators as policy instruments in the water–energy nexus in Spain since it is impossible to improve what cannot be measured.