Water is an essential element for life, not only because it is vital for humans but also because it has massive potential for making energy. It also makes a big difference in other ways for sustainable development. With the growth of human activities in manufacturing, waste treatment, construction sites, transportation (road, air and water), domestic activities (especially heating), agriculture and forestry, these waters will likely become more polluted. Therefore, protecting water is one of the most important things we must do for our growth. Therefore, this research was carried out to diagnose and describe the surface waters of the watershed of Oued Medjerda, Wilaya of Souk Ahras (North-East Algeria), as well as show the people in this region how polluted this river is and how serious this problem is. The Medjerda is also a crucial waterway for irrigation and thus plays an important role in regional agriculture. The results showed pollutants from urban, agricultural and industrial sources. These results were significant enough to show that the waterway requires rapid purification and that discharges and effluents from any source should not be dumped there.