Arid countries like Egypt need a lot of clean water for drinking, irrigation, and domestic usage. Given the increasing rate of population growth and urban development, it is crucial to assess groundwater quality to ensure suitability for various purposes. It is suitable for different purposes. . This study evaluates the groundwater quality in the Quaternary aquifer in Wadi Sudr using the WQI and several irrigation quality parameters. The study area's WQI and irrigation water parameters, such as RSC, SAR, KR, MH, Na%, and PI, were calculated to assess the suitability of groundwater for irrigation.  Additionally, spatial variation maps of major ions and WQI for the Quaternary aquifer were created and interpreted. The results show that the groundwater is unsuitable for human consumption. Because TDS levels exceed 1000 mg/l, and the groundwater samples are classified as unfit water (WQI <100). However, the groundwater's trace element concentrations (Cu, Zn, Mn, and Ba) are within acceptable drinking limits. Kelly's ratios, PI, and MH, along with the areal distributions of EC, TDS, SO₄^-2, and Cl^- reveal that the groundwater of the Quaternary aquifer can be categorized as good to permissible for irrigation. However, the samples were plotted on the Wilcox and USSl Staffs. Salinity diagrams and show that the Quaternary aquifer samples are unsuitable for the same purpose.