Geophysical and physicochemical methods were carried out to examine the effect of leachate on groundwater in a dumpsite location in Akwa Ibom State, Nigeria. This was done to ascertain the level of organic contamination in the wells located in the study area. The analysis of water samples from boreholes close to the dumpsite was done to constrain the interpretation of electrical resistivity data on the reality of the effect imposed by dumpsite leachate on the hydrolithofacies. The resistivity values of the underlying layers were observed to be lower than the overlying layer, an effect which may be associated with the infiltration of leachate into the underlying layers. The geohydrolayer resistivities range from 78.4 to 1,669.8 Ωm. The contour maps generated display the variations of the parameters. The elevation contour map indicates the flow of groundwater in a southwest–northeast direction which also depicts the direction of leachate flow. The physicochemical water samples show differences in concentrations of the physicochemical parameters. The concentrations of the ions in the water samples measured are compared with the WHO standard for drinking water. The sodium absorption ratio and sodium percentage show that the groundwater within the dumpsite has no negative effect on the subsurface.