Physico-chemical and bacteriological analysis study is important to assess the acceptability of drinking water quality. The water samples of ten tube wells and ten open wells were collected from five different villages of Supaul district, Bihar for the study of physical, chemical and bacteriological characteristics of the water samples. The results revealed that the pH varied from 6.5 to 7.0, the electrical conductivity 415-490 pS/cm, carbon dioxide ranged from 4.8-7.8 ppm the total alkalinity ranged from 152190 ppm total hardness 140-182 ppm dissolved oxygen 1.2-4.2 ppm ,BOD 1.2 -4.8 ppm and COD 38.068.0 ppm About 40% tube-wells were found to be polluted with FC (Faecal coliform bacteria) while those for 80% with TC (Total coliform bacteria). All the open wells were infected with FC and TC. The concentrations of testing parameter in the drinking water samples were beyond the permissible limit of the WHO and BIS. In this investigation it has been found that location of latrine，drain，bird’s excreta and sewerage line near tube wells and open wells are more likely the reason of contamination of water with both FC and TC. This maybe a major public health issue, and needs immediate attention forremedeal measures.