The region drained by wadi Baghai, North East of Algeria, characterized by a semi-arid climate, is the receiving environment for treated wastewater from Khenchela Wastewater Treatment Plant and the municipal untreated wastewater from the city of Baghai. This study aimed to monitor the water quality of Wadi Baghai using the physicochemical parameters (temperature, pH, dissolved oxygen, electrical conductivity, and major elements), pollution indicators such as chemical and biological oxygen demand (COD and BOD5), nitrogen matter, turbidity, total suspended solids, in addition to heavy metals. To evaluate its irrigation suitability, the sodium adsorption ratio, Kelly Ratio, soluble sodium percentage, permeability index, magnesium absorption ratio, cation ratio of structural stability, and irrigation water quality index were calculated. According to the results, the tested water did not exceed the agricultural reuse standards. The indices (SAR, Na%, KR, PI, MAR and CROSS) revealed that the water samples were suitable for irrigation. Similar results were recorded from IWQI with moderate to high restrictions. Classifications based on the riverside diagram illustrated that samples are classified as C3-S1 and C4-S1, therefore can be used for irrigation. Cluster analysis CA, based on the level of similarity, classified the sampling sites into two clusters: Cluster 1 (S1, S2), and Cluster 2 (S3).