Water scarcity and sanitation have constituted a major problem to the Nigerian government, this is because only 40 percent of the Nigerian population has access to potable water and over one hundred thousand children die yearly due to poor sanitation. This study evaluates the Water Poverty Index (WPI) that was designed by Caroline Sullivan for the monitoring and accessing of water at the international, regional and local levels. The study relies on secondary source for data gathering. This paper analyses the use of the WPI in five local government areas of Oyo state which indicated that the five local government areas are water-stressed regions because of the poor results in the WPI findings. It is on this ground that the study calls on the government to use the WPI for the monitoring of water availability so that adequate water policy can be initiated for proper integrated water management to address the problem of water scarcity. Finally, the study calls for future research on the WPI through an iterative process.