GEOG 431
Geography of Water Resources

Water Footprints and Virtual Water


There is a water crisis today. But the crisis is not about having too little water to satisfy our needs. It is a crisis of managing water so badly that billions of people - and the environment - suffer badly.

World Water Vision Report, 2000

An ecological footprint calculates the land that is needed for the products that sustain a nation as well as the waste needed to contain the waste of that population. A water footprint is an illustrative tool to measure total freshwater consumption for countries, states, counties, cities, organizations, or even a single person. A water footprint can be broken into three different sub-areas.

  • Green water – consumption of water or rainfall that is stored in the soil or plants.
  • Blue water – consumption of clean water resources from surface or underground sources where the water does not return as clean.
  • Grey water – water used in dealing with pollution and is defined as the volume of freshwater needed to bring the water to a quality that is capable and clean enough to be placed back into a natural setting.
  • Most water that is consumed comes from green water sources (primary production).
  • Manufactured products use mostly grey/blue water resources.
  • North American, European, Northern African, and Oceanic nations have higher water footprints.
  • Virtual water is all of the water used in the production of a product or service. This water can be traced among routes of supply and use worldwide.