Tread lightly: Understanding water footprints

Remember Winston Peters' $18 cabbages?

The dire prediction about the impact of Labour's pre-election water tax proposals must have involved a guesstimate of how much water it takes to grow a cabbage – albeit a vastly wrong one.

As competition for water intensifies around the world, the idea of water footprints is gaining currency as a way to compare the water efficiency of different foods. You've probably heard that it takes 1000 litres of water to produce a litre of milk, and rumblings and grumblings about the 16,000l needed to produce a kilogram of almonds. Read more