The results of a microbiological investigation of drinking water quality were analyzed. Water samples taken from the centralized and noncentralized water supply sources failed to meet hygienic standards in 14-18% of cases and those from water tubes did in 4-6%. Water samples from the household and community water use reservoirs showed the excess of the allowable levels of lactose-positive colibacilli and coliphages, which were 46.5 +/- 16.8 and 10.6 +/- 6.8% per dm3, respectively. L. pneumophila strains were isolated from the drinking water of railway carriages. Proposals are given to improve railway sociohygienic monitoring.