The interaction potential of rare-gas atoms with metal surfaces is calculated following the Zaremba-Kohn scheme. The attractive part of the potential is described by the usual van der Waals form. The change in the energy eigenvalues of the metal electron is calculated by using a pseudopotential formalism for the rare-gas-atom perturbation, the metal electrons being described by the atomic wave functions. It turns out that this model gives a qualitatively and semiquantitatively good description of the potential experienced by the metal s electrons at the surface. Calculations are performed not only for helium interactions with the noble metals, but also in the case of the other heavier rare gases.