Abstract : In Algeria, the quality of surface water is in an advanced state of deterioration in vitally important basins, mainly because of discharges of urban and industrial waste. Reservoirs are silting up and losing useful capacity, and the discharge of silt into watercourses into watercourses poses enormous ecological and environmental problems. The objective of this study was to evaluate the physico-chemical and bacteriological quality of water, collected from Oued El-Hammam, the Zit-Emba dam basin, and the city of Skikda's drinking water supply. Physico-chemical and bacteriological analyses were carried out monthly (from January to June) at four stations, focusing mainly on quantifying bacteria indicative of faecal contamination and determining the concentration of certain physico-chemical elements in the water. The results of the chemical analyses showed that the variation in the concentration of elements is closely linked to the interference of several factors (rain and geological substrate). From a bacteriological point of view, there was a high level of faecal contamination, with high levels of total coliforms, faecal coliforms and faecal streptococci, particularly at the Bouati-Mahmoud station, which could represent a major health risk for the region's inhabitants and animals. To ensure proper management of the water in the Zit-Emba dam and tackle the problem of pollution at this level, it is therefore necessary to apply the regulations governing domestic, industrial and thermal discharges.