Most of the dams are subject to a loss of capacity due mainly to three phenomena: water leakage, silting of the reservoirs and intense evaporation.the study of these phenomena is very important, because they can endanger the stability of the dam and reduce its useful capacity. This is the case in particular of the dams Gargar, Ouizert, Bouhanifia and Foum El Gherza. Located in arid areas where the water resource is becoming increasingly scarce. To this end, we have seen useful to present in this study the balance of total water losses of these dams. We have estimated the average interannual volume losses for the Gargar dam of 119.014 (hm3), Bouhanifia 45.45 (hm3), Ouizert 20.28 (hm3) and Foum El Gherza with 39 (hm3)