In areas where pipelines transporting technological water from drainage of the KGHM "Polska Miedź" S.A. copper mines are installed there are occasional instances of pipe failure with the resultant flooding of the soil with saline water. Based on studies undertaken immediately after the occurrence of pipeline failures and soil flooding, as well as at a later period, an attempt was made to describe the course of natural desalinization of soil that takes place as a result of percolation of precipitation. Examination and description was made for soils from 5 locations at which, in the years 1995-2008, failures of the above type took place. The study included determination of the soil salinity and of the composition of the cations exchange capacity of the flooded soils. A decrease in soil salinity was observed, as well as a decrease in the level of the exchangeable sodium percentage, taking place under the effect of precipitation water percolation through the soil. It was stated that the rate of decrease in soil salinity is in relation to the parameter characterizing soil texture. The salt leaching process proceeds notably faster in soils with a coarse texture compared to finely textured soils, and at the same time that process is faster in the surface horizons of the soil while being delayed in the sub-surface horizons. At the same time, a decrease was observed in the scatter of salinity and ESP results upon return to the state of equilibrium.