Through the global analysis of inundation disasters with regards to population and land elevation, we found that the largest number of people living in low-elevation land was in Asia. Population increase was also most rapid at these locations. Furthermore, through three case studies in Asia, we found that a critical land–water elevation difference was 1.5–2.0 m in relation to the prevention of disasters regarding groundwater and land as public goods, the protection of houses and buildings from tsunamis and the protection of temples from flooding.