In this work, an innovative mathematical approach for the total electric voltage in the electrocoagulation process (EC) was proposed. Contributions of electrodes activation and ions species transfer were modeled by analytical solving the non-steady Nernst-Planck equation. The electrical conductivity was adequately represented in terms of available positive ions species. A time-dependent equation that resembles a desorption-diffusion process was found to represent the electrode activation voltage. An Al electrode-based EC reactor was used to perform EC tests for assessing each electric phenomenon voltage. The data of electrical conductivity were well fitted by its proposed model, highlighting its effects on the total voltage. The anode activation voltage was responsible for the starting transient stage and modulating the total voltage profile. Finally, it could state that the time-dependent electrical conductivity has influenced the total voltage profile and drove the pollutant removal performance, acting on both activation and electric migration voltages intrinsically.