Overall a water footprint consists of three types of water: Blue, Green and Grey. Knowing the balance of these types in an overall footprint, as well as their distribution amongst the direct and indirect uses, tells us about the level of stress that a product or enterprise has placed on water resources.
• Blue water refers to the surface and ground waters and it is the water what we see in rivers and lakes.
• Green water, is the water held in the soil as moisture and cannot be extracted or piped away though it does evaporate from crop fields. Despite this, green water is essential for vegetation, whether it is natural or cultivated vegetation, and most of the crops grown in the world are grown using only green water.
• Whereas, the amount of grey water embedded in a product is the volume of water polluted as a result of the production process. It relates to the amount of water that is required to dilute the polluted water so that water quality is returned to an acceptable standard.