Coliform pollution in drinking water sources of urban and semi-urban settings of Kashmir: a growing concern for public health.

Coliform contamination has become a major threat to global water security and public health, particularly in developing regions where dependence on untreated or partially treated surface and groundwater remains high. As indicator organisms, coliform bacteria signal fecal pollution and the potential presence of pathogenic microbes responsible for waterborne diseases such as diarrhea, typhoid, and hepatitis. The Kashmir Valley, which has experienced a rapid population increase and lacks proper sewage treatment facilities, is particularly vulnerable to such dangers. This study assessed the bacteriological quality of drinking water sources in Srinagar (urban) and Ganderbal (semi-urban) districts during autumn and spring. A total of 200 samples were collected from tap water, groundwater, springs, and water treatment plants, and analyzed for total coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) using the most probable number (MPN) method. Multivariate statistical approaches, including non-metric multidimensional scaling (NMDS) and indicator species analysis (ISA), were applied to examine spatial and seasonal patterns in microbial communities. Results revealed widespread contamination, with 94% of samples in Srinagar and 88% in Ganderbal testing positive for coliforms. Groundwater and spring sources exhibited the highest contamination levels, while even treated water from filtration plants showed significant microbial presence. Coliform levels were consistently higher in autumn than in spring, with greater contamination in Srinagar, reflecting the influence of urbanization on the microbial loading. While environmental parameters such as temperature, pH, and dissolved oxygen affected coliform abundance, overall microbial community structure showed no significant relationship with these variables. The findings highlight the urgent need for improved water treatment practices, routine microbial monitoring, and infrastructure upgrades. Reliance on chlorination alone is insufficient; advanced disinfection technologies and improved sanitation systems are vital to ensure safe drinking water and guard public health in the Kashmir Valley.