Two of the biggest water variables, however, are population and diet. China's big population gives it one of the world's biggest water footprints (12% of the global footprint, as opposed to the United States' 9% share), and as the country develops, per capita meat consumption is also rising.ia Waterfootprint.org. Dark red countries have the worst footprints-between 2.1 and 2.5 million liters of water per capita each year. The top five biggest average daily users of water are the U.S., Australia, Italy, Japan, and Mexico-all five of these use well over 300 liters daily.