Seismic wave refraction method is a field test that normally uses to determine ground or subsurface profile particularly the depth of bedrock under the ground surface. However, due to rapid development in ground exploration the function of this test increased rapidly with the growth of urbanisation development especially for environmental sustainability purposes. In Malaysia the need of this test is in high demand due to rapid development especially in urban area as it is a cost and time effective method. The increase in demand for this kind of ground exploration is because it is a non-destructive method where no drilling is required in order to obtain the unseen underground profile and information. One of the most significant uses of seismic wave test is for detecting the unseen underground contamination layer. This paper presents result of a study that was carried out to detect the ground layer contaminated with leachate. Contaminated ground with leachate sometimes solidifies to form solid plum. These hazardous substances may seep through loose soil spreading to the lower gradient downwards until it reaches impermeable stratum or bedrock. In order to achieve the objective, this study was carried out using seismic refraction method to locate the contamination layer under the ground surface. A physical model by a wooden tank was constructed and filled in with contaminated ground layers as a simulation to real condition on field. The two layers of different types of ground material; sand and concrete are the main medium where the time of travelling wave was measured. Findings of this study shows that it is reliable to use wave propagation technique in detecting layer of contamination underground as the actual profile and seismic wave profile matched to each other.