The coliform group has been widely used as an indicator of water quality and has historically led to a public health protection concept. Presence of pathogens in drinking water may raise several health problems in humans from mild illnesses to serious waterborne diseases. In spite of several measures taken, water quality is always a pertinent issue prevailing in diverse water systems. So far, coliform contamination and diversity could not be adequately explored as traditionally used culture-dependent methods have a limited capacity to characterize microbiota from their respective sources. The study was designed for assessment of microbial diversity by culture-independent approaches placing emphasis on exploring the total coliform diversity in two drinking water reservoirs, Raman Pahad and Koilsagar of Mahabubnagar district, Telangana, India. Principal analysis based on 16S rRNA gene clone libraries revealed that Raman Pahad library clones belonged to genus Enterobacter (41.5%), followed by Citrobacter (25.03%), Klebsiella (17.86%), Escherichia (12.20%), and the least being Hafnia (3.39%). The clones in Koilsagar belonged to genus Enterobacter (46.42%) as the most predominant, followed by Citrobacter (32.14%) and Escherichia (21.42%). Comparatively, Enterobacter was observed to be the most predominant (representing 50%) of the total clones in both reservoirs.