Universiteit Twente
2400 litres of water for a hamburger

We don’t shower as long and when we do, we use a water-saving shower head. We turn off the tap to brush our teeth. That’s a good thing, but it doesn’t do much good, says water professor Arjen Y. Hoekstra. Ninety-five percent of our water consumption is used across the border, in the production of our food and clothing. Hoekstra developed the water footprint by analogy with the carbon footprint.

“Water is a scarce resource and literally a matter of life and death,” says Hoekstra. “Ultimately, life on earth depends on the land and water. We have always taken it for granted that there is enough water, but there isn’t. In many areas on earth, more water is used than is available. For example, because land is irrigated for crops that need a lot of water, such as cotton and rice.”

What are the consequences of this?

“If the amount of water used is dispropor­tionate to the level of precipitation and then the amount that flows through rivers, you get problems in the long run. Then lakes dry up and groundwater levels drop. This has an effect on nature and, in the long term, on the people who live there. Eventually there will be a shortage of water.”

What does the water footprint do?

“The water footprint shows how much water is consumed in the production of our food and other products. This is important because we do not see the majority of water consumption. In the Nether­lands it rains relatively often. So, you might be tempted to think that things are not so bad. But 95% of our water footprint is abroad. Roughly half of it is in areas where too much water is used. In this way, we contribute to the dehydration of areas where, for example, our vegetables and cotton are grown.”

What about our water consumption?

“Many products in the supermarket can only be there because water supplies elsewhere in the world are exhausted and polluted. We have to be aware of that. You can be economical with water in your household, and that’s a good thing. But the water consump­tion in the production of your food is many times greater. In many places, more water is used than is available. That is not sustain­able. For example, a lot of fruit and vegetables come from areas where irrigation depletes lakes and groundwater and affects the ecosystem. For example, strawberry cultivation in Spain (see box).

Wrong kind of water

Doñana National Park in the Spanish region of Anda-lusia has seen its groundwater level fall sharply and the nature reserve has halved in 30 years. The unique flora and fauna of the area is threatened, according to the World Wildlife Fund in January 2019. This is because groundwater is used in the adjacent area for the cultivation of strawberries, raspberries and other red fruits.

The World Wildlife Fund calls on consumers to demand guarantees from supermarkets that they do not sell fruit grown with ‘the wrong kind of water’. German, British and Swiss chains are already paying a lot of attention to this. According to Albert Heijn and Jumbo, their growers claim that they do not use groundwater illegally. However, according to the World Wildlife Fund, the monitoring of this is not watertight.

Arjan Y. Hoekstra

Working together to reinforce each other

How much water is used in production?

1 apple: 125 litres

1 cup of coffee: 140 litres

1 cotton T-shirt: 2700 litres

1 hamburger: 2400 litres

1 egg: 200 litres

1 sheet of A4 paper: 10 litres

What needs to be done to deal with water more efficiently?

“We need to distribute water more fairly. Governments must intro­duce water use rights to ensure that the availability and consump­tion of water is balanced. A benchmark per product can also help, so that you can compare the water consumption of a product with what is still reasonable for that product. Often, the water consumption is much higher than is really necessary. When you know that, you can avoid bad products. Finally, there should be international agreements and a system of rights, such as the one that exists for CO2. Although that is complicated. Such a system starts with setting a ceiling, a so-called cap. It also means that some countries must reduce their water consumption. But which country will do this voluntarily?”

What can we do ourselves to reduce our water footprint?

“You can already do a lot by reducing the intake of meat and by not wasting food. I myself turned vegetarian five years ago. It was a logical consequence of my story. I could hardly claim that meat production uses up so much water and eat meat at the same time. To produce one hamburger, you need 2400 litres of water. Meat also involves land use, greenhouse gas emissions and animal welfare. Moreover, we waste a lot of food, both in the production chain and at home. A lot of water was used for that food. For nothing, if you throw it away.”

How important is water treatment?

“Very important. If you treat water before reusing it in the production process, you don’t have to use ‘new’ water. If you treat wastewater before you discharge it, you have less impact on the environment. So water treatment helps. But companies can also look at the supply chain. For example, as a brewer you may treat your water, but 99% of the water is consumed earlier in the chain, for example in the cultivation of barley.”