Variations in functional parameters strongly affect the performance of the electrodialysis process, a promising approach for desalinating brackish water. Although the effects of operational factors have been qualitatively investigated in previously published works, the simultaneous effects of three important operational factors, applied voltage, superficial velocity, and temperature, have not yet been quantitatively described or presented in the form of a mathematical model. Therefore, the simultaneous effects of these operational parameters have not been shown in functional form in the previously published works. In this research, a laboratory-scale electrodialysis setup was used to qualitatively and quantitatively study the effects of operational factors by employing a set of full-factorial experiments with three replications at different levels of applied voltage per cell pair, superficial velocity, temperature, and feedwater composition. The nonlinear power-law functions were found for the effects of superficial velocity, applied voltage per cell pair, and initial feed concentration, while an Arrhenius-type function was found for the effect of temperature.