Palladium and copper-catalysed arylation of amines, alcohols and thiols, powerful tools for the construction of C–N, C–O and C–S bonds, are typically carried out in organic (and often toxic) solvents. Therefore the use of such a sustainable, benign solvent as water in this context has gained growing attention. This tutorial review presents the most recent advances dealing with palladium and copper-catalysed carbon–heteroatom bond formation performed in total or partial aqueous media. The particular and distinctive features of water which are apparently responsible for the acceleration and greater chemoselectivity of the aqueous protocols will also be discussed.