Drinking water quality in Cooch Behar Municipality, West Bengal, India: Assessment using WQI and public perception

Effective assessment and management of groundwater quality are essential for safeguarding the integrity of freshwater resources. Cooch Behar Municipality of West Bengal has been chosen for the present study due to its reliance primarily on groundwater for drinking water. The study focuses on assessing groundwater quality in the study area, a planned city with a long history of urbanization. The primary objective is to analyze various parameters relevant to drinking water and compute the Water Quality Index (WQI) with the residents' perception. Forty water samples were collected from Cooch Behar Municipality's Public Health Engineering (PHE) department, encompassing all 20 wards. Each ward provided one sample from a Deep Tube Well (DTW) and a Shallow Tube Well (STW). EC, Fe, TH, Mn, pH, TDS, Turbidity, Ca, and Mg levels were determined using standard instruments and methods, and analyzed geospatial techniques and statistical methods were employed. Results revealed concerning levels of manganese (Mn) and total hardness (TH), exceeding permissible limits in 82.5% and 75% of samples, respectively. While some parameters remained within acceptable limits, computed WQI values ranged from 63.28 to 162.67, indicating significant overall water quality concerns. Alarmingly, 45% of samples were unsuitable for drinking, with an additional 40% classified as very poor. Notably, demographic factors such as household income and education level correlated with perceptions of poor water quality. Policy implications suggest the urgent need for a well-structured management system to address these findings and ensure safe drinking water for residents.