Desalinated water is one of the non-conventional water resources where fresh water is produced before constructing a desalination plant. The brine resulted from the desalination process is usually injected into aquifer or discharged into the sea. The practice of disposing the rejected brine into the sea is common for plants located in coastal areas. The aim of this research was to simulate the brine disposal fate within an aquifer. The Visual MODFLOW numerical code was used to predict the salt concentration emigration over time in an aquifer. The model was calibrated using laboratory experimental data. The model results revealed that there is an acceptable agreement between the observed and simulated data.