Leachate reinjection is used in bioreactor landfills to accelerate waste degradation. Methodology tools are required to study the performance of such systems to guarantee optimal humidification of waste mass. Electrical resistivity sounding method is used to follow electrical resistivity variations related to moisture content. Two pilot zones are equipped with resistivity lines located across and along the horizontal perforated drains. Long term evolution of global resistivity of waste body hass been observed since 2002 and recirculation events produce electrical resistivity cartographies showing kinetic of leachate diffusion and influenced waste body areas.