We propose the use of a new protocol of self-potential measurements associated with a brine injection to locate leakages in earth dams and to quantify their permeability. Indeed, a brine solution injection upstream of an earth dam (in the assumed leakage zone) is able to change the electrical conductivity of the medium. In turn, this decreases the magnitude of the electrokinetic contribution of the self-potential signals that are related to the ﬂow of the seepage water. The evo-lution of this anomalous self-potential signal (expected to be positive with respect to a reference state prior the salt injection) can be measured at the ground surface with a network of non-polarizing elec-trodes. The seepage ﬂow inside the dam is localized from the evolution in space and time of the resulting transient self-potential signals associated with the transport of the brine. The mean permeability of the preferential ﬂowpath can be determined. This method is ﬁrst applied to a laboratory test to show how the passage of a salt tracer affects the self-potential response. Then, we apply this new methodology to a ﬁeld test site (a dam with a proven leakage) located in the south of France. At this test site, self-potential map-ping was ﬁrst performed to locate the preferential ﬂow path. Then, a network of non-polarizing elec-trodes was used to perform time-lapse self-potential measurements at the dam crest during a brine injection occurring upstream of the seepage zone. We used two lines of 16 non-polarizing electrodes each. From the time-lapse data, the permeability of the leaking area was estimated inside one order of magnitude.