In this research the authors have examined the quality of drinking water in schools by the microbiological and physico-chemical analyses of water samples from 140 schools in the region of ten municipalities of Zenica-Doboj Canton (Bosnia and Herzegovina). It is found that 18.57% of samples in the microbiological analysis, and 80.26% of samples in physico-chemical analysis, did not meet the standards prescribed for drinking water. Comparing the data in the statistic reports of health institutions and registration lists for infectious diseases in this area with the incidence of intestinal infections in the Region, the authors reached the conclusion that the incidence of intestinal infectious diseases and hepatitis A does not correlate to percentage of impure drinking water samples. This could be explained by lack of the sufficient and consistent registration of the infectious diseases which comes under the law.