From a water consumption point of view, the water-energy nexus is frequently split into the urban water cycle level and the building level. The former has been more explored and comprehends the abstraction, treatment and supply of potable water and the drainage, treatment and disposal of wastewater. At the building level the water-energy nexus manifests mainly by pumping and water heating. Water heating in buildings can represent a significant consumption of energy, which in many cases is difficult to quantify. In fact, in many countries residential water heating takes place within the home / apartment using sources of energy common to other domestic activities, making it difficult to split by end-use. The present communication explores a dataset comprising 3 years of monthly records of cold and hot water consumption in apartment buildings in Brussels by means of statistical analysis to assess cold and hot water consumption correlation. The aim is to provide a basis for extrapolation for other contexts were hot water consumption data is not available. DOC_AB_NL:From a water consumption point of view, the water-energy nexus is frequently split into the urban water cycle level and the building level. The former has been more explored and comprehends the abstraction, treatment and supply of potable water and the drainage, treatment and disposal of wastewater. At the building level the water-energy nexus manifests mainly by pumping and water heating.