The availability of water in homes is a necessary condition to guarantee several aspects of quality of life, including the health of the population. This study provides a quantitative analysis of this relationship in the municipality of Santa Cruz do Capibaribe, located in the semi-arid region of rural Pernambuco. Water availability was represented by the supply coverage index and population health by reported cases of acute diarrheal diseases. The data were obtained from the National Sanitation Information System, the Computerized Epidemiological Surveillance System of the Ministry of Health and the Brazilian Institute of Geography and Statistics. Normality was checked using the Shapiro-Wilk test, with a significance of 5%. Correlation and regression analysis was carried out by constructing a scatter diagram and inserting a linear model using the least squares method, subsequently evaluated by Pearson's correlation and determination coefficients. The results indicate the existence of a moderate negative linear correlation, with a coefficient of determination of 0.57. Therefore, it was possible to state that the reduction in water availability, which occurs in years of greatest drought, is related to the increased susceptibility of the population to acute diarrheal diseases.