The soil-water characteristic curve has become of great value in estimating unsaturated soil property function. The characterization of seepage, for example, in terms of hydraulic head gradient, and a coefficient of permeability function appears to be generally accepted. The use of nonlinear soil property functions for analyzing unsaturated soils problems appears to be gaining general acceptance. The soil-water characteristic curve then becomes a dominant relationship for understanding unsaturated soil behavior. This concept allows the soil-water characteristic curve can be used to compute approximate soil property functions for unsaturated soils.