An experimental investigation was undertaken to study the ability of Spectral Induced Polarization ( SIP) to monitor water infiltration in a silty clay loam soil. It was based on the coupled acquisition of tensiometer data and Spectral Induced Polarization ( SIP) spectra (1.46 Hz to 12 kHz) during the infiltration event created by an artificial constant rainfall rate of about 15 mm/h. The approach, which was applied both in the field and in a soil column, confirms the existence of a significant phase drop in the high-frequency domain ( typically greater than 1 kHz) during the first infiltration cycles. The interpretation of the tensiometer and SIP data show that this phase drop is correlated with the water filling of pores in the [30-85] mu m diameter range. The phase drop is qualitatively and quantitatively interpreted as a Maxwell-Wagner effect associated with the electrical heterogeneity of the soil. It could correspond to the transition between two physical states. In the first state before the arrival of the wetting front, highly polarized and wet aggregates are embedded in an electrically isolating phase, i.e., air. In the second state after the arrival of the wetting front, structural pores between the aggregates are filled with a connected and conducting phase, i.e., water, leading macroscopically to a decrease in bulk soil polarizability. The experimental and theoretical results of this study suggest strongly that the SIP method can be used to monitor the water filling of structural or draining pores in the field. This original result requires validation in other sites.