Grocery stores do it. So do restaurants. Schools, farmers, you and I. We all waste food. At the local, state and federal level, discarded food is widely recognized as a serious environmental and socioeconomic problem. Today, the U.S. Department of Agriculture (USDA) and Environmental Protection Agency (EPA) launched a national Food Waste Challenge to encourage reduction of food waste.

Cognizant of the fact that food waste comprises one-third of New York City’s more than 20,000 tons of daily refuse, Mayor Mike Bloomberg also recently announced that more than 100 restaurants will participate in the first-ever Food Waste Challenge, a new city government program to reduce the amount of organic waste sent to landfills. Participating restaurants have pledged to reduce 50 percent of the food waste customarily sent to landfills through composting and other waste prevention strategies.

Among the many negatives associated with food waste is the added strain–through excess consumption and production–it places on our finite freshwater resources. Surface waters and groundwater are already under tremendous stress from various industries as well as from climate change, which has intensified the global water cycle causing drought and torrential rains.

For those of you who are familiar with GRACE’s Water Footprint Calculator, you know that what we eat every day represents about 50 percent of our total water footprint, which includes the enormous volume of “virtual water” needed to produce our food. The water footprint concept helps us to better understand, among other things, the complex relationship between agriculture and water resources, and in particular, the water embedded in our food. Given the water-intensive nature of growing, processing, packaging, warehousing, transporting and preparing food, it follows that wasted food means wasted water.

When you crunch the numbers, about 25 percent of all freshwater consumed annually in the US is associated with discarded food. Having trouble visualizing how much water that is? Well, on a global scale, by one clever comparison, it’s a little more than the volume of Lake Erie.

Our food system’s impact on water resources goes beyond water use, withdrawal and consumption; agricultural pollution negatively impacts water quality in groundwater, streams, rivers, lakes, wetlands and estuaries. According to the US Environmental Protection Agency, agricultural activities that cause pollution include “poorly located or managed animal feeding operations; overgrazing; plowing too often or at the wrong time; and improper, excessive or poorly timed application of pesticides, irrigation water and fertilizer.”

Fortunately, many people and organizations have given a lot of thought to how we can reduce food waste including the Natural Resources Defense Council, the United Nations Environment Programme, the US Environmental Protection Agency, Tristram Stuart, Jonathan Bloom, Food Shift, and of course, us here at GRACE.

There are many effective ways to reduce food waste–and when you save food, you save water, another environmental benefit that New York City and Mayor Bloomberg can tout.