The article discusses the urgent problem associated with solving the problems of salt transfer in soils and is devoted to numerical modelling of the transference and diffusion of salts in soils, in which the total porosity of the soil is divided by the fraction of “through” and “dead-end” pores with the corresponding concentration of the solution. A brief review of scientific publications devoted to this problem is given. To study and predict the process of the spread of harmful substances, a mathematical model and a numerical algorithm for computer experimentation have been developed. The solution was obtained using a method based on the use of quadrature formulas in combination with the differential sweep method for a system of ordinary second-order differential equations with arbitrary linear boundary conditions. The concentrations of salts in the “through” and “dead-end” pores, respectively, were studied at various values of the filtration process. The results are shown in the graphs.