Using the Belgian soil map for mapping groundwater vulnerability. Groundwater vulnerability mapping is a critical activity in the implementation of the water resources protection policy. The vulnerability of groundwater bodies is largely determined by the properties of the overlying soil. The soil map and associated data bases contain spatially distributed information, which can be easily introduced into the vulnerability mapping procedure. In this paper, soil information is used in the vulnerability mapping procedure through the "partial vulnerability from the soil" (VPS) concept. Three methods are presented for mapping the VPS: the first method uses the soil map only, while the second and third methods use data from the soil analytical data base. The three methods are applied to mapping the vulnerability of the Brusselean sands groundwater body, in the center of Belgium. The three approaches yield three different vulnerability maps, and explanations for these differences between approaches are given. Finally, a strategy is presented for validating the different approaches to mapping the partial vulnerability from the soil.