[Objective] The current study investigates the microbial quality of drinking water using various microbial detection methods. [Methods] We analyzed the microbial quality of still bottled drinking water using flow cytometric cell count, ATP assay, AOC (assimilable organic carbon) assay and cell viability test. [Results] We found that the flow cytometry allowed fast and accurate discrimination of the live/dead bacteria and detection of the micro-scale AOC. Our results also showed that ATP is a better indicator than the heterotrophic plate counts of the actual active microorganism content in still bottled drinking water. [Conclusion] The results suggested that the flow cytometric cell count and ATP assay are more suitable methods for assessing microbial quality in bottled drinking water than the conventional heterotrophic plate count method.