Water quality is crucial for balancing water demand and availability, and ensuring it meets human and environmental needs is essential for sustainable development. This study developed a Water Quality Index calculating tool (Arc G-WQI) using spatial modeling to determine subsurface water type and suitability for various purposes. The tool was developed using Python Programming Language and Model Builder for Esri ArcGIS desktop 10.6. Arc G-WQI allows secure and structured storage of data from analyses of field-collected samples in a geodatabase and accelerates WQI computation, allowing faster and more accurate classification. A case study was conducted to validate the tools applicability in assessing groundwater quality. Groundwater samples were collected from 85 sites in the Ismailia Canal in the eastern Nile Delta. The Arc G-WQI-Tool stored WQ data in a geodatabase and created thematic information layers which are then utilised to create maps displaying water quality parameters distribution. Next, the groundwater quality index (WQI) was computed and a map of the WQI was created. According to the outcomes, groundwater in the southern and western parts of the research area is classified as good water appropriate for a variety of uses. However, groundwater in the research areas northeastern parts is classified as very poor water and could be used to cultivate salt-tolerant plants. The study concluded that the spatial tool can be a reliable technique for monitoring and managing groundwater quality in the water supply system.