Food and Water: Why Some Foods Have Larger Water Footprints Than Others

Food and Water: Why Some Foods Have Larger Water Footprints Than Others

Food and water are closely connected. The Water Footprint of Food Guide helps users figure out how much water their food uses and why.

Food and water are closely connected. The Water Footprint of Food Guide shines a light on just how much water it takes to make some of the most common foods you eat every day.

It takes a lot of water to produce food, whether it gets that water as rain or from irrigation. If you’re trying to reduce your water footprint, examining the water footprint of your food is an effective way to do it. The Guide is a handy way to look up many of the foods that make up the American diet, from meat to vegetables to pasta, even pizza. In addition, items can be displayed by their large, medium and small water footprint sizes. 

What does water footprint “size”  mean, and why are some larger than others?

Factors That Affect the Water Footprint of Food

The water footprint of food varies greatly from item to item. It depends on how much water the item requires for it’s production, where it was produced, the local climate and hydrologic conditions, and how much pollution was generated in its production. 

Perhaps the biggest impact on the water footprint of a particular food item is how much water it takes to grow or make the food, but that’s not the only factor affecting its footprint. Whether a food is grown in a wet or dry place, local water availability, local climate patterns, and processing requirements all play a role in determining how large or small the water footprint actually is. 

How and where food is produced has a big impact on the different parts of its water footprint – the blue, green or grey water footprint: 

Food crops planted in areas that receive adequate rainfall for agriculture will have a larger green water footprint, whereas crops planted in dryer areas that require irrigation will have a larger blue water footprint. Food crops with a higher green water footprint are generally less of a problem unless there is a drought. 

Food crops suffering under drought are often irrigated with water resources that are needed elsewhere, like for residential users and healthy ecosystems. This might not seem like a problem in most typically “wet” locations, however, droughts can happen anywhere and water resources can suddenly be constrained in areas that have never been strained before.

Water pollution happens when runoff introduces fertilizer and pesticides from fields and nutrients and chemicals used in industrial farms from manure piles and lagoons into waterways, increasing the grey water footprint. Untreated wastewater from agricultural operations can make water unusable, decreasing water availability. 

The Foods with the Smallest and Largest Water Footprints 

All food takes water, and, as shown in the Guide, even items considered to have a “small” water footprint can take as much as 20 gallons of water to produce. It’s eye-opening to look at foods grouped by their water footprints and understand which foods take more water and why. In the Guide, we’ve broken down the groups as follows:

  • Large water footprint: >75 gallons of water
  • Medium water footprint: 20 gallons to 75 gallons of water
  • Small water footprint: < 20 gallons of water

Meat tends to have a larger water footprint than many plant-based food items, as well as dairy and eggs, which puts most meat products in our “large” water footprint group. The main reason is because animals eat a lot of feed, whether it’s grain on feedlots or forage and grasses on pasture. Grains are often irrigated, which increases the blue water footprint. Pasture grasses are typically rainfed, which increases the green water footprint. In addition, the animal is then processed (slaughtered and butchered), and the products are packaged and shipped to the market like other food items. It all adds up to some of the largest water footprints we can “eat.” 

Large water footprints don’t stop with animal products, though. The food item with the highest water footprint in our Guide, in an ounce-to-ounce comparison with beef, is…chocolate . Many nuts and some dried fruits are also in the “large” group. If you’re someone who enjoys these indulgences on a regular basis, it might be worth looking at how much water it takes to eat these foods so frequently.

The group we’ve labeled as having a “medium” water footprint contains dairy, eggs, beans (sometimes called pulses), many fruits and a bunch of different processed foods. It seems clear that producing protein takes water. In fact, according to the Water Footprint Network, “For beef, the water footprint per gram of protein is 6 times larger than for pulses.”

The “small” water footprint group includes most of the vegetables, especially root vegetables, and some of the fruits like melons, berries and most citrus. If you really want to make a dent in your water footprint, eating more from this group and less from the “medium” and “high” groups will help bring it down. Read on for tips about how to really make an impact and reduce your water use by changing your habits and your diet. 

Small Changes to Dietary Choices and Habits Add up to Big Water Savings

There are a few ways to reduce your water footprint by changing your dietary habits and what you eat. 

Perhaps the most meaningful step a person can take is not wasting food. In addition to water, it takes many resources to produce food, including labor, animals, land, chemicals like fertilizers and pesticides, packaging materials like plastic and cardboard, energy and a lot of money. When edible food is thrown away, all those resources are wasted.

Changing up how you eat can also make a huge difference. Eating a diversity of foods with a variety of water footprints (focusing on foods from the “small” group) can ensure that certain foods aren’t being overconsumed and, consequently, overproduced. Eating lower down the food chain – eating more plant-based foods – will generally lower your water footprint. 

Even swapping out a single food item per day can make your diet more sustainable, according to a new study from Tulane University. For example, the study authors calculated that eating a serving of turkey instead of ground beef would cut a person’s water-use impact by 30 percent in a meal (it also reduces greenhouse gas emissions). 

Finally, if keeping track of what you’re eating based on your food’s water footprint is too much math to think about, then reducing your water use can be as easy as practicing Meatless Monday. Just don’t eat meat one day per week and you’ll cut your meat consumption by 15 percent (that math is easy — one day in 7 is almost 15 percent of the week). If you replace your meat products with beans and other pulses, it could have a big impact on your water footprint.

If you’re interested in checking out the math and more about your food, the Water Footprint of Food Guide has got you covered. Use the guide to create your plan to reduce your water use and lower your water footprint. Small changes to your diet are an easy way to make it happen.