We use far more water than we realize – for example, a pair of jeans cost 11,000 litres of water to produce. This “hidden” or “virtual” water is invisible to most of us, which is why the Water Footprint Network in the Netherlands is researching the “water footprints” of the things we buy, “to try and make that link between production and consumption, and to help people understand how their choices impact global water supplies,” says Professor Arjen Hoesktra, creator of the water footprint concept. “There are lots of things that people can do, but in the end we are really talking about food,” he says. Around 86 percent of world water use goes to crop production, and what we eat accounts for about 70 percent of the average person’s water footprint.
Wondering how much water it takes to produce the food you eat every day? Here’s what goes into your daily bread…
Apple: 70 litres
It takes 70 litres for a “big mac,” almost entirely from the water soaked up by the trees in an orchard during the apple’s growth. Crop irrigation is also the main factor in an orange’s water footprint, which is 50 litres.
Red wine: 240 litres
It takes 240 litres of water to produce a 250 mL glass of red wine, almost entirely from vineyard irrigation. Beer interestingly comes in lower with 75 litres of water for the same sized glass.
Coffee: 140 litres
A single cup of black coffee takes 140 litres of water to produce. It requires 21,000 litres to grow a kilo of coffee beans, which translates to about 140 litres for the seven grams of java needed to make one cup of coffee. Add in another 20 litres of water for a splash of milk (20 mL), and another 13.5 litres if you take sugar (two teaspoons).
Hamburger: 2,400 litres
A burger costs 2,400 litres of water, almost entirely due to the 2,300 litres needed to create the 150 grams of meat. Beef is one of the most water-needy things you can eat because of how much time and energy is needed to raise cattle: A cow usually produces about 200 kg of boneless beef, taking about three years from birth to slaughter. And in its lifetime, a cow usually eats 1,300 kg of grains, along with 7,200 kg of hay and other roughage, consuming more than 3 million litres to grow the crops over those three years. On top of that, throw in the 24,000 litres of water the cow eats and the 7,000 litres of water for “servicing” (washing the animal and its waste away). And if you slap on a slice of cheese (say, an ounce) that brings the total up to 2,550 litres.
Eggs and toast: 480 litres
A slice of bread will chalk up 80 litres in water, thanks to the water needed to grow the wheat. And a single egg costs 200 litres in water to produce the grain needed to feed the chickens.
Chocolate: 2,400 litres
Are you ready? It takes 2,400 litres of water to produce just 100 grams of chocolate.
Of course, water footprints for the same product made in different parts of the world will vary. But just because a product from one region of the world has a higher water footprint than from another country doesn’t make it a more ecologically prudent choice. Wines from, say, rainy British Columbia will have soaked up more water in their growth than wines from more arid regions like California. But they represent a more water-wise choice than wines from somewhere like drought-stricken Australia, a continent that is suffering acutely from the ravages of poor water management.
Remember: It’s not just what you eat, it’s where it comes from that counts, too.