Water footprint

The global water footprint is 7450Gm3/yr, which is in average 1240m3/cap/yr. The United States of America has an average water footprint of 2480m3/cap/yr whereas China has an average water footprint of 700m3/cap/yr. The factors that affect water footprint are:

1. Total volume of consumption, which is generally related to gross national income of a country. (eg. USA, Italy and Switzerland)
2.  Water-intensive consumption pattern such as high consumption of meat. Average meat consumption in the United States is for instance 120 kg/yr, more than three times the world-average (Eg USA, Canada, France, Spain, Portugal, Italy and Greece)
3.High consumption of industrial goods. 
4. Climate. In regions with a high evaporative demand, the water requirement per unit of crop production is relatively large. (Eg. Senegal, Mali, Sudan, Chad, Nigeria and Syria)
5. Water-inefficient agricultural practice. (Eg. India, Thailand, Cambodia, Turkmenistan, Sudan, Mali and Nigeria).

Adapted from A. Y. Hoekstra • A. K. Chapagain, 2005, Water footprints of nations: Water use by people as a function of their consumption pattern, Water Resour Manage (2007) 21:35–48

Global average virtual water content of some selected products, per unit of product

Product	Virtual water content (litres)
1 pair of shoes (bovine leather)	8000
1 hamburger (150 g)	2400
1 cotton T-shirt (250 g)	2000
1 glass of milk (200 ml)	200
1 glass of apple juice (200 ml)	190
1 bag of potato crisps (200 g)	185
1 glass of orange juice (200 ml)	170
1 cup of coffee (125 ml)	140
1 egg (40 g)	135
1 glass of wine (125 ml)	120
1 slice of bread (30 g) with cheese(10 g)	90
1 glass of beer (250 ml)	75
1 apple (100 g)	70
1 orange (100 g)	50
1 slice of bread (30 g)	40
1 cup of tea (250 ml)	35
1 microchip (2 g)	32
1 potato (100 g)	25
1 tomato (70 g)	13
1 sheet of A4-paper (80 g/m2)	10
Source: A. Y. Hoekstra · A. K. Chapagain, 2005, Water footprints of nations: Water use by people as a function of their consumption pattern, Water Resour Manage (2007) 21:35–48