The role played by the various components of the intermolecular interaction in some clusters involving water molecules is discussed. In particular, the main features of some rare gas-water (Rg-H2O), alkali ion-water (M + -H2O) and small pure water (H2O) n clusters have been investigated and the tendency of multicenter van der Waals components (size repulsion + dispersion-attraction) to coalesce on a single interaction centre located on the oxygen atom as the strength of the interaction increases, is discussed. The interplay between induction and electrostatic components for the various systems is also analysed and the impact on the formulation of the intermolecular potentials of relevance for molecular dynamics simulations is considered.