Using the HyperChem programme, the influence of water on the properties of some monosubstituted aromatic compounds was studied from the point of view of the intermolecular interactions. There have been estimated some physico-chemical parameters of the benzene, fluorobenzene, chlorobenzene, bromobenzene, iodobenzene, nitrobenzene, phenol and aniline when solved in water, surrounded by one or two solvation spheres. The boundary lengths, total energies, border levels energy, dipole moments, polarizabilities, wavelengths and the probabilities of the electronic transitions have been obtained.