Water to eat: plant-based food that requires most water

Elena Vardanian
22.02.2021
3 min read

By 2030, projections from the National Intelligence Council suggest that a world of approximately 9 billion people will require 35% more water, 40% more energy, and 50% more food (1). Agriculture is highly dependent on accessibility to adequate sources of water. Today, in the United States, agriculture is responsible for 80% of all water consumed (2).

It takes a surprising amount of water to grow and process food, because crops cannot grow without water, especially not without irrigation water. In fact, more than two thirds of our total water footprints come from our diet, mostly because of all the “virtual water” needed to produce food. Virtual water is the “hidden” component in a production process, which contributes to the total water footprint.

What is a water footprint?

A water footprint is an indicator of how much fresh water goes directly and indirectly into a product (3). Water footprints can be applied to a city, a business, an individual or, yes, our food. When we say “water footprint of foods”, it goes beyond direct water use and takes into consideration the water used during a product's entire supply chain.

How thirsty is our food?

Different food leaves different amounts of the water footprints. For example, it will take 1,847 gallons of water to produce 1 pound of beef (or 15,500 litres per 1 kilo) (5). As the chart shows, meat and poultry are the most water-intensive food products, along with nuts (6).

Tree nuts like almonds, pistachios, walnuts, and cashews are actually some of the most water-intensive crops grown today. Peanuts are far more water efficient than other nuts because they are more similar to potatoes and grow below the ground (7). Almonds, especially peeled, consume 32 times more water than goobers.

Table 1. Water print of nuts, gallons per pound

Peanuts
Chestnuts
Almonds
(with shell)
Hazelnuts
Pistachio
Cashews
Almonds
(peeled)
59
330
963
1,260
1,362
1,704
1,929


We’ve already discussed that one can minimize the harmful impact on the environment by cutting the consumption of red meat and choosing a plant-based diet. But let’s look at the anti-top of non-animal food that requires most water.

Almonds

The three most water-intensive nuts on the market are grown in water-stressed California. The state produces 82% of the world’s almonds, 98% of the U.S.’s pistachios, and 99% of the U.S.’s walnuts (7). 

Almond production uses around 2 trillion liters of water per year and is contributing heavily to groundwater depletion and land degradation, according to Professor Yoshihide Wada, deputy director of the water program at the International Institute for Applied Systems Analysis. California has also been repeatedly stricken with severe drought in recent years. Groundwater levels in the Central Valley, where most almond crops are grown, dropped by almost a half-meter annually during California's historic seven-year drought in 2011, according to a study by Cornell University (9). A regular and dependable supply of water increases how much food we can grow, making repeated droughts in the U.S. nation’s “breadbasket” especially alarming.

Avocado

Another water consuming tree is avocado. It takes an average 237 gallons of water, 5 full bathtubs, to grow just one pound of “green gold’, according to the Water Footprint Network, a Dutch organization that advocates for better management of water resources. The brunch favorite's water consumption is four times the amount needed to produce the same amount of oranges or ten pounds of tomatoes.

Farmers in the Chilean province of Petorca are used to overpump groundwater and divert water from emptying rivers because they need to water perennial crops, which require water year-round. Irrigation is the only way to sustain rapidly growing avocado production and exports, said Professor Wada (8). In arid Petorca, every cultivated hectare of avocados requires 100,000 liters of irrigated water a day, according to WaterAid.

Coffee

Coffee is both a labour – and resource-intensive crop to grow. Water Footprint Network estimates that a standard European cup of coffee or espresso (125 ml) requires around 37 gallons (140 litres) of water (9).

Much of coffee's water footprint results from the beans' cultivation. To that end, NGOs such as Rainforest Alliance and Fair Trade USA engage farmers across the globe to work together on reforestation projects (10). Preservation of the watersheds and preventing erosion programs by Rainforest Alliance became a forest’s lifesavers farmers’ money keepers. Companies, like Kraft Foods, with its brands of coffee that includes Kenco, Gevalia, and Maxwell House, have promised to source more sustainable coffee certified by Rainforest Alliance and other third-party certification groups.

Olives\Olive oil

Olive (Olea europaea L.) is considered drought tolerant and trees can survive on shallow soils with little supplemental water beyond winter rainfall (11). Overall, 361 gallons of water used to produce 1 pound of table olives. Sounds good, unless you won’t look further through the product chain.

Olive oil on the other hand is the product which contributes the largest percentage of water footprint in the Mediterranean diet in Spain and the US. Refined and virgin olive oil requires around 1,760 gallons of water per pound. Despite olives being millennial, local and landscape-adapted trees, their high water footprint values make olive oil one of the major water consuming products, even more than meat and dairy (12).

Chocolate

It takes an astonishing 450 gallons (1700 liters) of water to make a typical 3.5-ounce (100-gram) chocolate bar. That’s about ten bathtubs of water for one bar of chocolate (13). Sweet, isn’t it?

This huge footprint can largely be attributed to the water required to grow cocoa beans. Since chocolate is popular all over the world but grows within a 10-degree latitude band around the equator it appears that water print is very large because chocolate has to travel far away from producers. In fact, more than half of the water consumed to produce chocolates eaten in the United States comes from rain falling in West Africa.