A new method to estimate the properties of electrolyte solutions has been outlined in this work. The models for electrolyte solutions at the Bonn-Oppenheimer level have always been perceived to be very complicated to solve by either integral equation theories or Perturbation theories. The present work identifies simpler BO level models called Square Well Simple Civilized model (SQWSCM) and Square Well Water Simple Civilized Model (SWSCM). The properties of SWSCM model have been obtained by simulations and hydration numbers have been found to be comparable to experimental results. In order to obtain an analytical solution for these models a Thermodynamic Perturbation type approach has been outlined. The appropriate reference fluid for the TPT approach has been identified. The properties of this reference fluid have been obtained by simulations.