water Program

Water Footprint - Concepts and Definitions

What is a Water Footprint?*

Your water footprint  G  is the amount of water you use in and around your home, school or office throughout the day. It includes the water you use directly (e.g., from a tap). It also includes the water it took to produce the food you eat, the products you buy, the energy you consume and even the water you save when you recycle. You may not drink, feel or see this virtual water,  G  but it makes up the majority of your water footprint. 

Water footprints can be calculated for individuals, households, businesses and countries. In fact, you can take our Water Footprint Calculator to find out how what you do in and around your home affects your water use. 

Why Do Water Footprints Matter?

Freshwater (non-saline water) is vital to life, yet as our population and prosperity grow, so does our use of freshwater. This is always a concern since water is already scarce in parts of the US and the rest of world. Climate change impacts increase the likelihood of changes to the water cycle that lead to potentially prolonged periods of drought. Reduced water supplies will add to water insecurity both here and abroad.

Water footprints help individuals, businesses and countries because they reveal water use patterns, from the individual level all the way to the national level. They shine a light on the water used in all the processes involved in manufacturing and production of our goods and services. An accurate water footprint also accounts for how much water is contaminated during manufacturing and production because that water is made unusable and is, essentially, taken out of the system. 

While there can never be a perfect water use assessment or audit tool, the water footprint gives everyone – from individual consumers to business managers to public officials – a solid frame of reference and helps us all be more efficient and conservative with our water.

What Makes a Blue, Green or Grey Water Footprint?

Within the water footprint concept, water use is measured in terms of the volume of water consumed, evaporated and/or polluted, in a given amount of time. The Water Footprint Network splits water footprints into three corresponding elements:

Blue Water Footprint: the surface water and ground water consumed (i.e. evaporated or incorporated into a product) during production processes.

Green Water Footprint: the rainwater consumed (i.e. evaporated or incorporated into the product) by the product.

Grey Water Footprint: the freshwater required to mix and dilute pollutants and maintain water quality according to water quality standards.

Examples of how each of these contributes to an item's total water footprint can be found in the Water Footprint Network’s Food Gallery.

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The source of all water footprint content comes from the Water Footprint Network(WFN). The concept of water footprints was created by Dr. Arjen Hoekstra, who along with the others at the WFN, developed the framework and established the international organization as the foremost research network in the discipline.