Bacteriological assessment of drinking water of Islamabad Capital Territory, Pakistan

This study was conducted to evaluate the bacteriological quality of drinking water of tube wells, filtration plants, and water supplies from various sectors of Islamabad Capital Territory (ICT), Pakistan. Fifty-five water samples were collected from 18 filtration plants, 26 tube wells, and 11 water supplies and analyzed for total heterotrophic bacterial count (THBC) by spread plate count method, total coliform (TC), and fecal coliform including Escherichia coli by most probable number technique along with physicochemical analysis. Results showed that 21 (38%) out of 55 samples were found contaminated with heterotrophic bacteria. Among the 55 sites tested in triplicates, 15% (n = 8) were contaminated with TC and 13% (n = 7) were contaminated with E. coli (EC). Different bacterial strains were isolated and identified by using API 20E method. According to this study, 14.5% of the water sources of ICT did not meet the safe limits for drinking water as described in the WHO guidelines.