The Laúca Dam is located at km 307.5 of the Kwanza River (measured from its mouth), about 47 km downstream from Capanda Hydroelectric Project, near the village of Ya N hangue Pepe in the province of Kwanza Norte - Angola. Usually dam foundations are designed and constructed along the eroded channel rivers and supported on the rocks, and many of these rocks are fractured, and generate some discontinuities with a high degree of hydraulic conductivity of the dam foundations .This dissertation aims to assess and to evaluate the seepage conditions throughout the foundations of hydroelectric Laúca. This evaluation is normally made using the tests of loss of water with pressure and interpreted using the proposal of Maurice Lugeon, i.e., the well-known in the practice of dam engineering as the Lugeon test. This test is performed in rock masses through boreholes and different stages, aims to determine the hydraulic conductivity and the behavior of the fractured rock mass, taking into the consideration the water flow through the discontinuities and fractures. Using the Lugeon set of results, it can be estimated important engineering characteristics such as: the volume and the type of flow and representatives values of the equivalent mass of the hydraulic conductivity. All this information is useful to establish the grouting procedure and also to verify the performance of the treatment carried out to reduce leakage through the dam foundation.