Vaastu Shastra says, a plot with soil that has a large salt content is considered as inauspicious plot. The ground water table should be minimum 10-12' below the existing ground level and maximum 30'. It should not have any sanitary back-filled or reclaimed soil or rubbish, bones, hair and other filthy material. The soil should be fertile and free from any decrepit or dead material. The depth of the foundation may depend on the load bearing capacity of soil, the number of storeys that are going to be constructed and the materials used. A house Shouldn't be build on sand soil.