One of the common dangers of earth dams is seepage, or leakage through either the dam body, the dam foundation, or the culverts. This article introduces results of utilizing the improved multi-electrode electrical exploration method to survey the seepage area in the Dong Do dam in Minh Tan village, Minh Tri commune, Soc Son district, Hanoi, Vietnam. The results show two possible seepage anomalies in the survey profile along the heartbeat line, one seepage anomaly in the survey profile at the center of roof 1, one seepage anomaly in the survey profile at the center of roof 2 and a large heterogenous area in the first profile from the 185th meter position to the flood spillway staring from the surface down to a depth of 11m that the previous drilling could not reach these areas. These results confirm the effectiveness of the improved multi-electrode electrical exploration method in investigating hidden hazards in general, and the seepage areas in the dam in particular.