Valuation of water quality index (WQI) is one of the simplest, easily understandable, and efficacious techniques to evaluate the quality and suitability of water for drinking as well as other purposes. This research was aimed to investigate the drinking water quality of tube wells from different areas in Khulna City, Bangladesh, by developing the WQI. Water samples from 59 tube wells were collected from different locations during the pre-monsoon time. pH, electric conductivity (EC), dissolve oxygen (DO), total dissolved solid (TDS), chloride (Cl⁻), nitrate (NO₃⁻), and total hardness of the collected water samples were analyzed for the calculation of WQI. The mean value for pH, EC, DO, TDS, Cl⁻¹, NO₃⁻, and total hardness was 7.30, 1650 μS/cm, 1.60 mg/l, 1188.7 mg/l, 414.6 mg/l, 0.029 mg/l, and 52.03 mg/l, respectively. The calculated WQI values for individual places were distributed spatially through mapping by using ArcGIS software. Based on the WQI values, the drinking water was categorized into excellent, good, poor, very poor, and unfit for drinking purposes. The calculated WQI values ranged from 40.11 to 454.37 with an average value of 108.94. Among all the groundwater samples, 11.86% were excellent, 54.24% were good, 23.73% were poor, 1.69% were very poor, and 8.47% were unfit for drinking purpose based on WQI. The results showed that the groundwater quality of most of the studied areas of Khulna city could be considered safe and suitable for drinking barring the elevated EC and chloride content in some areas. Since Khulna city is situated in the southwestern part of Bangladesh and gradually approaches toward the base level of the Bay of Bengal which might be the source of salt concentration in the groundwater of Khulna city, Bangladesh.

水质指数（WQI）的评估是最简单，易于理解且有效的技术之一，可用于评估饮用水和其他用途的水质和适用性。这项研究旨在通过开发WQI来调查孟加拉国Khulna市不同地区的管井的饮用水水质。在季风前的时间从不同的位置收集了59口管井的水样。的pH值，电导率（EC），溶解氧（DO），总溶解固体（TDS），氯（氯^- ），硝酸根（NO ₃ ^- ），和所收集的水样品的总硬度进行了分析WQI的计算。用于pH平均值，EC，DO，TDS，氯^-1，NO ₃ ^-，总硬度分别为7.30、1650μS/ cm，1.60 mg / l，1188.7 mg / l，414.6 mg / l，0.029 mg / l和52.03 mg / l。使用ArcGIS软件通过映射在空间上分配了每个位置的计算WQI值。根据WQI值，饮用水分为好，好，差，极差和不适合饮用。计算出的WQI值范围为40.11至454.37，平均值为108.94。在所有的地下水样本中，基于WQI的优良水质为11.86％，优良水质为54.24％，不良水质为23.73％，非常贫困水质为1.69％，不适宜饮用的水质为8.47％。结果表明，除某些地区升高的EC和氯化物含量外，Khulna市大部分研究区的地下水水质可认为是安全的，适合饮用。