Electrical conductivity probes (4-electrodes Wenner array system) have been designed and constructed in order to evaluate the spatial distribution of solute leaching into soils. Experimental studies have been carried out to investigate the volume of sampled soil of these probes. The probes have also been successfully used to monitor changes in electrical conductivity at various depths in a soil column following application of a tracer pulse (CaCl2) during a leaching study. The measured breakthrough curves have confirmed the good accuracy of this measurement technique.