Free Virtual Water calculator with clear step-by-step results.
Virtual water is the volume consumed across a product's whole supply chain, which for food and textiles dwarfs household taps. Splitting it into green water from rainfall and blue-plus-grey water from irrigation and pollution matters because only the latter competes with other users.
Total virtual water
Litres = mass kg x water footprint per kg
Blue and grey water
Blue + grey = total x (1 - green water share)
Green water is rainfall the crop would have transpired anyway. Blue water is abstracted from rivers and aquifers and directly reduces what is available for other uses, so it carries far more scarcity significance.
No - they are global averages. Beef from rain-fed pasture and beef from irrigated feedlots differ by several times, and local water scarcity changes the meaning entirely.