Water holds a particularly important place in our lives; it is a precious resource called: blue gold. Unfortunately, pollutants and pollution in general are the main causes of the degradation of the quality of water resources in the world. In this intention we have focused our research on a qualitative study of surface waters of the Oued Mellègue watershed (North East of Algeria), which is a tributary of Oued Medjerda (Souk-Ahras), whose objective is to estimate the intensity as well as the origin of the pollution that has contaminated this water course However, the results obtained reveal that the waters of this wadi are totally polluted and deteriorated, and they have lost all their physical and chemical qualities. And they become contaminated to the point that they have become harmful for the public and for the fauna and flora that shelter. So the research of solutions to the pollution of water resources must be in full swing, because the future of water is intimately linked to that of humanity. It must therefore be preserved and protected rigorously and with great accuracy.