In soil machines Permeability is one of the important Engineering properties, as it governs rate of settlement of saturated compressible soil layer and rate of flow of equifer. Permeability is that property of soil which permits flow of water through its interconnecting voids. The instrument to measure permeability is called permeameter. The results are used for pumping groung water, for functioning sites excavations, design of dams etc. Tests can be performed on remoulded or undisturbed samples using constant head or falling head method.