Fluctuation of the groundwater level in karstic areas results from dierent cumulative eects, such as water in®ltration from precipitation, human interference on the water resources of a certain area, the Moon's tide eect, air pressure ¯uctuation, etc. It is practically impossible to measure these eects directly, generating the need for estimations by indirect methods, applied to the registered water level in monitoring wells. The conventional tool to determine latent or background eects governing variability or ¯uctuations is factor analysis. Since ordinary factor analysis has been elaborated for independent observations and the observed karstwater levels at a certain location represent realizations of time series, dynamic factor analysis has to be used instead. The obtained dynamic factors can then be identi®ed as the above mentioned eects. Once the intensity of an eect has been determined at every observation site, its spatial structure and prediction is aimed to be given. To achieve this goal, universal kriging is used and analyzed for the spatial process of estimated loadings of dynamic factors. The present paper concentrates on the eect of in®ltration. The obtained map of the loadings of the dynamic factor corresponding to in®ltration provides valuable information on the intensity of this eect. Its importance from the environmental protection point of view is immense, because it helps to determine those potentially dangerous areas where in®ltrating contaminated water can quickly, and in vast quantity, reach underground water resources.