The objective of our study is to present a sensitivity analysis to deformation of a water flow model in swelling media. The water flow model considers a three-dimensional deformation of an unsaturated soil. The sensitivity analysis is carried out with two types of swelling soil, a vertisol of the Senegal River valley and a mixture of loam and bentonite. In the vertisol and at this scale of study, the water model does not need to take into account deformation. On the other hand, for more swelling soils like a mixture of loam and bentonite, we showed that it is necessary to take into account deformation in the water flow model.