The subject of this study was the postmining landfill located near the village of Buków in southern Poland. The pile is situated about 200 m from the Odra River in the vicinity of the “Buków” flood polder. The resistivity and induced polarization imaging methods were applied to recognize the influence of the deposited waste on the underground water. In the storage yard area, under a thin and non-continuous impermeable cover, there is a water-bearing layer of considerable thickness. This layer enables the transport of chlorides and sulphates from the landfill. Since the aquifer in the investigated area is not homogeneous containing numerous impermeable, clayey interbeddings, the unambiguous interpretation based only on the ERT results of would not be reliable. The results using induced polarization allowed some of the contaminated zones to be unambiguously identified. The results obtained show that the postmining waste and hydrotechnical objects built of them influence the underground water, and areas of contamination can be identified successfully by the combination of resistivity and induced polarization imaging, even in the complex lithological structure.