While drinking water intake usually varies between 2 and 3 liters/person/day and other domestic water requirements for personal and household hygiene necessitate between 30 and 300 liters/person/day, the production of food requires much more: between 2,000 and 5,000 liters/person/day.
Most of the water that is used on crop production comes from rain that is stored in the ground (known as green water).
Worldwide, rainfall provides 90% of the water used by crops.
Of the world’s total land area, 13 billion hectares (ha), 12% is cultivated and approximately 27% is used for pasture. Of the 1.5 billion ha used for crops, 277 million ha of this is irrigated (18%).
In terms of population, crops equate to .25 ha/person.
Historically, irrigation comprises between 70% and 80% of all water uses. There are some countries that use up to 90% of their water for irrigation.
As a result of increased cropping intensity, the area of harvested crops under irrigation is expected to increase 30% by 2030.
Also by 2030, the amount of water that is expected to be allocated to irrigation will go up by 14%.
Source: UNESCO Water Portal, October 2007