In this paper the first step is taken toward a first-principles molecular theory of the liquid-semiconductor interface. The focus is on the degree of rigor that must be applied to the solvent in order to obtain a realistic description of the interfacial electronic properties. To accomplish this, two different water solvent geometries on the H/Si(111)1X1 surface are assumed, and the electronic structure of the system is calculated using two different models for the water molecules, one which includes the electrons of water explicitly and one which does not. It is found that for a realistic description of the surface electronic structure it is necessary to use an ab initio description of the solvent molecules for at least the first layer due to the electronic state mixing. The issues of broken symmetry of the crystal surface and possible dissociation of the solvent molecules are also discussed.