This study presents an experimental study on change of hydraulic conductivity of the soil and its impact on contaminant transport through the soil using numerical analysis. It emphasizes over the fact that hydraulic conductivity of soils may change with time if the pore water pressure is maintained for long. The reason may be hydro-mechanical coupled effect, the particle dynamics in the pore water and its interaction with the surrounding soil. In this study, chosen soil sample is silty sand. A constant head permeability test is performed for over two months such that it simulates the field condition where laterally confined soil is overlain by normal water and particles in Brownian motion are supposed to percolate into the soil along with water. In addition, if the water is contaminated, the contaminants may also infiltrate into the soil and may advance to considerable depth within the soil. To analyze the contaminant transport through the soil, a numerical method based on finite volume approach has been used. Contaminant transport has been studied for varying hydraulic conductivity, for its weighted average value with respect to time and arithmetical average value. The results show that the contaminant transport is relatively faster in case of varying hydraulic conductivity with time as compared to average values. Thus, variable permeability shows more rational behaviour of contaminants transport in the soil. This study is only preliminary; however, extensive study on hydraulic conductivity behaviour of soils subjected to continuous pore pressure is still required.