Drinking water quality of Chattogram city in Bangladesh: An analytical and residents' perception study.

Residents of Chattogram city areas in Bangladesh use drinking water from three sources, namely CWASA (Chattogram Water supply and Sewerage Authority), groundwater (tube-well), and commercial jar. In this study, we examined the quality of drinking water from these sources following an analytical and residents' perception. Water samples (both untreated and treated) from above three sources were collected from six locations across Chattogram city, and pH, total dissolved solids (TDS), total suspended solids (TSS), bicarbonate, electrical conductivity (EC), salinity, and microbial load were studied following the state-of-art testing methods. A total of 149 respondents were interviewed to understand their perception on the physical properties of water. The pH value of water from all sources and locations and irrespective of treatments, varied from 6.54 to 7.02. TDS of tube-well water in two locations exceeded the standard limit (1000 mg/l). In most locations, TSS varied from 40 to 1888 mg/l (treated and untreated) against the standard value of 10 mg/l, while bicarbonate of CWASA and tube-well water in most locations was also higher than the permissible amount (500 mg/l). Except for jar water, EC of CWASA and tube-well water (treated and untreated) in most locations were higher than the standard value (500 μS) and a similar situation was observed for salinity content. The microbial load was found beyond the permissible limit (0 CFU/ml) for all sources and locations. These parameters of water quality have also been reflected in residents' perceptions of drinking water. Respondents reported an unpleasant odour (56%), the presence of suspended particles (17%), and so CWASA water is not good for drinking (76%). Authorities (CWASA) need to take action toward a safe drinking water supply for residents.