The Water Footprint of Your Food: Meat vs Plants

Every food you eat has a hidden water cost. From the irrigation of crops to the drinking water for livestock, the water footprint of your diet may be the most underappreciated environmental metric. The differences between animal and plant foods are staggering.

What is a water footprint?

A water footprint measures the total volume of freshwater used to produce a product, from farm to plate. It includes three components: green water (rainwater stored in soil), blue water (surface and groundwater used for irrigation), and grey water (freshwater needed to dilute pollutants). The concept was developed by Professor Arjen Hoekstra at the University of Twente and has become the standard framework for assessing water use in food production.

The most comprehensive global study on water footprints in food production was published by Mekonnen and Hoekstra in 2012 in the journal Ecosystems. Their data, covering the period 1996 to 2005, remains the benchmark reference used by the UN, the World Bank, and the Water Footprint Network.

The numbers: water per kilogram of food

Here are the water footprints of common foods, measured in litres of water per kilogram of product (global averages from Mekonnen & Hoekstra, 2012):

Animal products

• Beef — 15,400 litres per kg. A single quarter-pound burger patty (113g) requires roughly 1,740 litres of water. The majority comes from growing feed crops (corn, soy, alfalfa) over the 2-3 year lifespan of a beef cow.
• Sheep/goat meat — 8,763 litres per kg.
• Pork — 5,988 litres per kg.
• Chicken — 4,325 litres per kg. Lower than beef primarily because chickens have a much shorter life cycle and more efficient feed conversion ratio.
• Cheese — 3,178 litres per kg. It takes approximately 10 litres of milk to produce 1 kg of cheese.
• Eggs — 3,265 litres per kg.
• Milk — 1,020 litres per litre of milk.

Plant foods

• Pulses (lentils, beans, chickpeas) — 4,055 litres per kg. This sounds high, but pulses are protein-dense. Per gram of protein, pulses use far less water than any animal product.
• Rice — 2,497 litres per kg. Rice is the most water-intensive staple grain because paddy rice is grown in flooded fields.
• Wheat — 1,827 litres per kg.
• Maize (corn) — 1,222 litres per kg.
• Potatoes — 287 litres per kg.
• Vegetables (average) — 322 litres per kg.
• Fruits (average) — 962 litres per kg.
• Tomatoes — 214 litres per kg.

Why is beef so water-intensive?

A beef cow eats roughly 1,300 kg of grain and 7,200 kg of roughage (grass, silage, hay) over its lifetime to produce about 200 kg of boneless beef. Growing all that feed requires enormous amounts of water. According to Mekonnen and Hoekstra, 98% of beef's water footprint comes from the feed alone — not from the drinking water for the animal or the water used in processing.

The feed conversion ratio tells the story: it takes approximately 7 kg of grain to produce 1 kg of beef. For chicken, it is roughly 2 kg of grain per kg of meat. For tofu, the ratio is essentially 1:1 — soybeans are the product.

The water footprint of any animal product is larger than the water footprint of a wisely chosen crop product with equivalent nutritional value.

Water scarcity: why this matters now

According to the United Nations, 2.3 billion people live in water-stressed countries, and by 2025, 1.8 billion people will live in areas with absolute water scarcity. Agriculture accounts for approximately 70% of all freshwater withdrawals globally (FAO, 2020). In regions like the American West, Central Asia, and sub-Saharan Africa, water use for animal agriculture directly competes with drinking water and crop irrigation for human food.

The Colorado River, which supplies water to 40 million Americans, has been in crisis for over two decades. Alfalfa grown for cattle feed is one of the single largest consumers of Colorado River water, accounting for an estimated 32% of the river's total consumption according to a 2023 analysis by the Pacific Institute.

What about almonds and avocados?

Critics of plant-based diets often point to water-intensive crops like almonds (3,448 litres per kg) and avocados (1,981 litres per kg). These are valid concerns — but context matters:

• Almond milk vs cow's milk: Producing one litre of almond milk requires approximately 371 litres of water, compared to 628 litres for one litre of cow's milk (Poore & Nemecek, 2018). Oat milk requires just 48 litres.
• Portion sizes: People eat 30g of almonds as a snack. They eat 200g of steak as a main course. The water cost per serving, not per kilogram, is what matters in practice.
• No vegan diet depends on almonds or avocados. These are luxury items, not staples. A diet centred on grains, legumes, potatoes, and seasonal vegetables has a dramatically lower water footprint than any diet containing animal products.

The total dietary water footprint

A 2012 study by Mekonnen and Hoekstra estimated the average water footprint of different diets. Their findings were striking:

• Meat-heavy diet (Western average) — approximately 5,000 litres of water per day.
• Vegetarian diet — approximately 2,600 litres per day.
• Vegan diet — approximately 2,000 litres per day, potentially lower depending on food choices.

That means switching from a typical Western diet to a vegan diet saves roughly 3,000 litres of water per day — over 1 million litres per year. The Water Footprint Network has confirmed these estimates, noting that reducing animal product consumption is the single most effective way for individuals to reduce their water footprint.

What you can do

Your dietary choices are the most powerful lever you have for reducing your personal water footprint. Here are concrete steps:

• Replace beef first — beef has the highest water footprint of any common food. Swapping beef for beans in a single meal saves over 4,000 litres of water.
• Choose oat or soy milk — both have dramatically lower water footprints than cow's milk or even almond milk.
• Eat more legumes — lentils, chickpeas, and beans are protein-rich and water-efficient when measured per gram of protein.
• Reduce food waste — wasted food means wasted water. Plan meals, use leftovers, and compost scraps.
• Eat seasonally and locally — out-of-season produce often requires more irrigation. Local seasonal vegetables have the smallest footprint.