A common saying in Japanese is "mizu to anzen wa tada" ("water and safety are free"), meaning they can be taken for granted.
But with water becoming increasingly scarce in a growing number of regions around the world and with developing countries facing a population explosion, Japan must collaborate more with the global community to secure water resources, according to Taikan Oki, an associate professor at the Kyoto-based Research Institute for Humanity and Nature.
Japan must also review its food imports, which account for about 60 percent of its food supply, because they use up massive water resources in exporter countries, according to Oki.