Example: On average, 155 gallons of water are required to grow one pound of wheat. For a cup of coffee: 37 gallons. For a pair of leather shoes: 4,400 gallons. And so forth.
Worldwide, the average water footprint, per person, is 323,410 gallons per year. In the U.S., it's about twice that.
Agriculture accounts for about 70% of all water use in the world, so on a consumer level, the article suggests, swapping veggies for meat can conserve up to 750 gallons of water per day. A less severe change is not throwing away food, which can be hundreds of times more wasteful than taking a longer shower.