Water quality can be considered a key contributor to both health and disease for humans. To obtain more advanced information about water quality the principal component analysis (PCA) was applied using the drinking water supply network data during four seasons in 2018 in Souk Ahras city/Algeria in order to extract principal factors that can explain the quality of drinking water. These factors aim to bring together the main explanatory elements of the water quality and their order of responsibility on the quality of the water through physicochemical parameters measured in situ. During the course of study 14 parameters were used for the characterization of the quality of drinking water in Souk Ahras city, these parameters were replaced by six (6) principal components explaining approximately 65.33% of the variance of the data. The study highlights two main problems, the strong signs of the presence of harmful germs and probably malfunction in part of the equipment of the processing and distribution facilities; and second, amount of the residual chlorine in water