The paper presents a brief analysis of methods of foundation soil purification from oil products. A method of electrochemical soil purification is suggested using the system of operational geophysical monitoring in natural conditions. A full-scale test method of controlled electrochemical soil purification and the experimental setup are described. The results of engineering-geological surveys of the soil massif artificially saturated with oil products (waste oil, gasoline) are presented. The formation of drainage zones, accumulation of petroleum products during electroosmotic transfer, soil structure changes caused by the phase transformation and dissolution of petroleum products are presented. the phenomenon of coagulation of oil products in soil during the electrical processing leading to the increase in the particle size in sand and clay components due to changes in the electrical soil resistance. The experiments prove the efficiency of electrochemical cleaning of low-permeable sandy-clay soils.