Basra gets its water from the Shatt al-Arab, the waterway formed by the Euphrates and Tigris rivers. Then it takes its way to the community through the water treatment plant. The tap water samples were studied to assess their bacteriological characteristics and their suitability for drinking purposes. Ten different localities and two bottled drinking water companies at Basra city were selected in this study. Bacteriological examination of water samples included the most probable number of presumed coliforms and fecal coliform bacteria. The results showed that the total number of coliforms was detected in all water samples taken from the ten sites. These samples were also having a positive result using another methods EMB medium and Membrane Filtrations Technique. There was no evidence of coliforms presence in two samples of bottled drinking water. The most common group of organisms used in water quality control are coliforms. These organisms represent the bacteria usually present in the intestinal tract of animals and humans. Biological contamination of water may occur during transportation from the plant to the consumer or during storage in the tank. Improving and expanding existing water and wastewater treatment systems is likely to provide good, safe and sustainable sources of water in the long term.