We write about virtual water a lot.  You could almost say it’s the unofficial theme of the Drought Diaries.

To understand virtual water better, we’re going to explain how it’s calculated.  Almost everything you eat, wear, or buy begins life as a plant.  This is obvious with fruits and vegetables, but a little less clear with other products; we’ll get to that in a second.  All plants need water to grow.  If your crops are grown in a region with a rainy climate, you’re good to go, but if your agriculture is somewhere like notoriously dry California, where half of the nation’s domestic vegetables, nuts, and dairy come from, you’re going to need artificial irrigation.  All of the water sprayed over the crops from the time the seeds are planted until their harvested contributes to their virtual water footprint.

But that’s not all.   What about meat, for example?  Well, your livestock needs to drink water, so that’s a bit of their virtual water impact.  However, animals also need to eat, and if your livestock isn’t free range (and even then, their diet may be supplemented with grain in the winter), then farmers are feeding your cows, chickens, and pigs grains and hay, so the virtual water for all that produce counts toward the final meat product.  That’s why meat has such a massively larger impact on water resources than plants.

Then there’s processing.  A lot of the artificial procedures to change food’s taste, color, and shelf life use water, which is why a kg of corn needs 1,220 liters of water while corn syrup needs almost double that, in spite of them being made of the same thing.   So while a bag of potato chips or a slice of Kraft Singles may not seem like a product that would deplete our water supply, each bag of the former is soaking up 151 liters and the latter’s using 2,230 liters per pound through production of the ingredients and subsequent processing.

Finally, there’s transportation costs to consider.  Each gallon of gas needs 2 gallons of water.  A product’s virtual water impact is determined by every bit of travel it does from the farm to your dinner table.  If you’re buying raw produce from local farmers at a farmer’s market, you’re probably reducing your virtual water footprint a bit, even on water-intensive crops.  If, however, say, corn is harvested and transported to a beef farm, then the cow eats the corn and is transported to a slaughter house, then that beef is transported to a plant to be converted into jerkey, then that jerky is transported to your local convenience store – well, a Slim Jim hardly seems worth its impact.

So clearly, your geographic location makes a big difference in your virtual water footprint.  However, there’s one other factor to consider: the native environment where your food is grown.  Take a look at the avocado, for example.  Most avoacados are grown in Mexico, which has a lot more rain than California.  As a result, Mexican avoacados aren’t irrigated as much, and end up needing only 121 liters of virtual water compared to California’s 280.   Even though they’re transported further, their footprint is smaller.

If you want to eat water-conscious, you need to consider any number of factors, such as the water needed to grow its ingredients, whether it contains meat or animal products, where it was grown and the climate there, whether it was processed, and how far it was transported.  Sound like a lot to keep track of?  Luckily, Drought Diaries are here for you to help you navigate these virtual water channels.