The water supply in Lahore, Pakistan, is totally dependent on groundwater, which is creating a number of challenges due to mismanagement of groundwater resources and an exploding population. An unconfined aquifer is receiving pollutants from a poor drainage system, non-scientific landfills, and through untreated effluents from industries and domestic sources. A study was conducted to evaluate groundwater qualities: total dissolved solids, total hardness, pH, alkalinity, and turbidity. Using geographic information system (GIS), drinking water quality zones were developed with groundwater chemical analysis data. Applying World Health Organization (WHO) drinking water standards, 61% of the total area is excellent, 27% is good, 9% is moderate and 3% has poor quality, while only 5% of the area is excellent, 29% is good, 34% is moderate, and 32% is not suitable for drinking purposes using Pakistan Standards and Quality Control Authority (PSQCA) drinking water standards. According to 2010 groundwater chemical analysis data, most areas have suitable zones for drinking purposes; however, there is high risk of continuous contamination. Finally, this study identifies highly contaminated groundwater zones and makes it convenient to find actual pollutants. Therefore, plans are needed to protect the aquifer.