Our water footprint measures the amount of water used to
produce each of the goods and services we use. This footprint can be measured
for a single process
There are three types of water footprints: green, blue, and grey. The
green water footprint is water from precipitation that is stored in the root
zone of the soil and evaporated, transpired or incorporated by plants. The blue
water footprint is water that has been sourced from surface or groundwater
resources and is either evaporated, incorporated into a product or taken from
one body of water and returned to another, or returned at a different
time. The grey water footprint is the
amount of fresh water required to assimilate pollutants to meet specific water
quality standards. 
Embedded water, a blue water footprint, is the water used to
produce food and non-food products. According to Waterwise, sixty five percent
of the water that we consume is from the foods we eat. To put this in
perspective, it takes about 1,100 drops of water to produce one drop of coffee
and it takes about 136 drops of water to produce one drop of tea. In just one
tomato there is 13 liters of water and in one glass of milk there is 200
liters. It is estimated that by 2025, two-thirds of the global population will
live in areas of water stress.
Today, I ate ground beef in my chili and chicken with my lunch.
One pound of beef requires 1,799 gallons of water. Broken down, this is
irrigation water for grain and feed, grasses for feed, and additional water for
the cow to drink and process. One pound of chicken requires 468 gallons of
water. This includes irrigation
water for grain or feed and additional water
for drinking and processing. The beer I drank this weekend required 689 gallons
of water to produce one gallon. Most of this water is for the growth of barley.
As for non-food sources, clothing requires more water than
most people would think. One t-shirt requires 713 gallons of water. Almost half
of this is for irrigation and another 41 percent is rainwater that evaporates
off the cotton fields. The last 14 percent of the water is for treating
wastewater from fields and factories.
Less than one third of 1% of the 3% of fresh water globally
is available for human use. The rest of the water is frozen in glaciers or
polar ice caps, or is out of our range and unable to use. Water is becoming an
extremely limited resource that is being shared with more and more people as
the population continues to increase. There are impacts of excessive
consumption. Water consumption in agriculture alters natural water cycles,
degradation of water bodies is on the rise, reservoirs alter stream-flows and are
the cause of loss of high quality agricultural land, and maintaining
infrastructure for water supply and use is very expensive. Of course, there are
benefits to preserving our global water supply. Many programs are implemented
to protect this rapidly depleting resource, but it is up to us to preserve what
is left for future generations. 