Do you know the water footprint of these common foods?

The food on our plates can require a surprising amount of water to get there. Read on to find out about the most and least water-intensive foods.

What is a water footprint?

Calculating the ‘water footprint’ of food is a way of measuring how much water was used to produce it.¹ If you’ve ever tended to a garden or even just a houseplant, you’ll know that plants need water. The crops that we grow to eat are no different. Though different varieties need differing amounts, all need water to survive and make it to our plates (and stomachs).

The animals we raise for food drink water too – though most of the water footprint of a steak, for example, comes from the plants grown to feed cattle rather than water being gulped down by the cows themselves.

Water is also used in the processing of food after it’s grown. It can take 2 litres of water to rinse a single kilogram of lettuce, for example.²

Read how the water footprint of food is calculated.

Beef is the most water-intensive food

The food that needs the most water to produce is bovine meat, such as beef, at over 15,400 litres per kilogram.³ Other meats, like lamb, goat, pork and pig meat, use between 6000-9000 litres of water per kilogram.³ Chicken ranks the lowest compared to other types of meat, at just 4500 litres of water per kilogram of meat.³

The water footprint of meat in general is higher than plant crops because of all the plants that need to be grown in order to feed these animals.

Editor's Note: It's important to differentiate between green, blue, and grey water footprints. "Green water footprint" refers to water from rain stored in the soil and plants, whereas "blue water footprint" refers to irrigation from surface water like rivers and lakes. "Grey water footprint" refers to the water needed to dilute contaminants from agricultural practices. It's helpful to know that meat has a much bigger water footprint than most pulses, but it's only part of the story. A cow that ate rainfed grass rather than irrigated grain could have a similar overall water footprint, but the ecological impact would be different. Similarly, a water-intensive crop like almonds might be problematic in a dry region like California but a suitable crop for a region with plenty of natural rainfall.

Dairy has a high water footprint

Because dairy is an animal product, it also has a high water footprint. It takes more water to produce a kilogram of butter (at around 5500 litres) than it does to make a kilogram of chicken, for example.³

Milk fares a bit better: it takes around 1000 litres of water to produce a kilogram. Making cheese uses a lot of milk, so its footprint is higher, at around 4000 litres per kilogram.⁴

Plant-based foods are not off the hook

Pulses and nuts also need lots of water to make it to the dinner table. On average, nuts have a water footprint of around 9000 litres per kilogram. Pulses come in at around 4000 litres.³

For those in need of good news, you should know that vegetables are the shining stars of water consumption, averaging just 300 litres of water per kilogram.³ Fruits come in a little higher at 900 litres.³

Making fair comparisons

It’s worth thinking about how much of each foodstuff we tend to use when comparing water footprints.

For example, a kilogram of milk roughly equals a litre – an amount some people could easily drink over a couple of days. A kilogram of butter would, however, take a lot longer for most people to eat. Even though butter’s water footprint is higher by weight, your personal water footprint could be affected much more by gulping down milk compared to using a little butter on your toast.

Another way is to compare foods based on the amount of water used per gram of a specific nutrient. Butter actually has just half the water footprint than most oil crops when you look at it this way, at 6 litres of water per gram of fat, versus 11 litres for oil.³ And per gram of protein, beef has a water footprint 6 times larger than that of pulses.⁵

Read '6 Tips To Reduce Your Water Footprint of Food'

Finding ways to use less water

The earth is a blue planet, but only 2.5% of our water is drinkable.¹ Global water scarcity and a growing world population with more mouths to feed than ever means we urgently need to find ways to use less water.

Some researchers are using bioengineering to create crops, like new rice varieties, that need less water in the first place.⁶ Another innovation uses satellite images to monitor water loss from agricultural land to help farms figure out how much water their crops need to stop wasteful overwatering.⁷ And researchers are also coming up with new ways to clean water after it’s been used to rinse produce so it can be recycled.²