Photo: Justin Sullivan/Getty Images
That slice of pizza New York City Mayor Bill de Blasio is munching on needs a lot of water — 42 gallons, to be exact. The flour, cheese, and sauce require 18, 21, and 2.5 gallons of water, respectively.
Photo: Jan Somma-Hammel, Associated Press
A single egg takes 53 gallons of water to produce. 53! Chickens need grain feed that requires a lot of water to grow and water for drinking and irrigation.
Photo: ABDULLAH POPE, AFP/Getty Images
A loaf of bread needs 288 gallons of water to produce. According to the Water Footprint Network, 15 percent of total water footprint to all global crops went toward wheat production.
Photo: Jasper Juinen, Bloomberg
And you thought a slice of pizza or a single egg was bad. A bar of chocolate — typically weighing around 0.1 pounds — requires 317 gallons of water to produce.
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Rice, like most grains, requires a lot of water to be produced. A pound of rice needs 449 gallons of water to produce.
Photo: Rich Pedroncelli, Associated Press
Chickens need less water than their bovine counterparts, but chickens still leave a sizable water footprint. A pound of chicken meat requires 468 gallons of water to produce.
Photo: Justin Sullivan, Getty Images
A pound of beef requires a whopping 1,799 gallons of water to produce. Cows drink a lot of water in the first place, but when you include the amount of water-intensive grain and grass they consume, the water footprint adds up very quickly.
Photo: Joe Raedle, Getty Images
Vegetables in general need a lot less water. A pound of lettuce only needs 30 gallons of water. In absolute terms, it's a lot. In relative terms, it's a drop in the bucket.
Photo: Michael Macor, The Chronicle
Tomatoes take even less water than lettuce. A pound of tomatoes needs only 24 gallons of water to produce.
Photo: MOHD RASFAN, AFP/Getty Images
Now that you know the water footprint of your favorite foods, what can you do in this time of drought? Eat more vegetables! Try out Meatless Mondays, for example, and conserve water.
Photo: John Storey, Special To The Chronicle
Another way to conserve usable water is to support sustainable farms which minimize the use of synthetic fertilizers and pesticides. Fertilizers and pesticides generally increase energy input for food production and sometimes pollute drinkable water.
Photo: Sarah Rice, Special To The Chronicle
Lastly, don't waste food! Food is energy. Food is water. To waste food is to waste energy and water.
Photo: Michael Macor, SFC