This study evaluates the drinking water quality in Dhaka and Keraniganj using the WeightedArithmetic Water Quality Index (WQI) method. Six samples were collected from deep tube wells,household water sources, and bottled water brands. Key parameters analyzed include pH,dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), total hardness(TH), and chloride concentration. WQI values ranged from 37.75 to 62.17, classifying water qualitybetween "Good" and "Poor." The study highlights the need for continuous groundwater monitoringand improved water treatment practices in urban and peri-urban areas of Bangladesh.