Milk

Global average water footprint: 1000 litres of water for 1 litre of milk.

Drinking a glass of milk (200 ml) costs 200 litres of water.
Drinking the same volume of orange juice or apple juice would cost 170 and 190 litres of water respectively.
Drinking a plain glass of water requires only little more than the water itself.

Drying 1 litre of milk produces 0.2 kilogram of milk powder.
Hence, the water footprint of milk powder is 5 times higher than that of milk, i.e. 5000 litres/kg.