The coefficient of permeability is a characteristic of soils, specifically it is linked to Darcy's Law which refers to the flow of fluids through soils. The permeability coefficient, generally represented by the letter k, is extremely variable, depending on the type of soil.

The permeability coefficient is a function, among other things, of the viscosity of the water, which is in turn a function of the temperature (permeability is normally established at 20 C); the size and continuity of the pores; and, the presence of cracks and discontinuities.

Classification of soils according to their permeability coefficient.

Some guideline values ​​are given in the following table.

The determination of permeability, in the laboratory, is done through permeameters.

The determination of this characteristic of the aquifer can also be evaluated in the field, for this there are several methods, among them: permeability tests.