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May 15, 2024Arizona Water Footprint
Those of us living in the desert should know better than anyone that water is life. Water is certainly the lifeblood of our existence in the desert. Despite this obvious fact, it is often difficult to comprehend the full extent of the importance of water in our daily lives.
A good place to start is with the recognition that 60-70% of our body weight is made up of water. We need plenty of water just to function properly and each person needs to directly consume approximately one gallon of water per day, as a basic metabolic minimum (Mayo Clinic, 2022).
Each person’s water needs will vary depending on their diet, environmental conditions such as temperature and humidity, and a person's activity level among other factors. For example, someone hiking in the desert on a warm spring day will need to consume at least one quart of water per hour to maintain proper hydration.
It is commonly estimated that the average American needs about 102 gallons of water daily for personal use, which includes water to drink, bathing, cooking, toiletries, etc. (Kobir, 2024; and Philadelphia City Government, 2024). The United States Geological Survey (USGS) estimates that the average American needs 80-100 gallons per day for basic use and consumption, commonly referred to as indoor use (USGS, 2019). The Arizona Department of Water Resources (ADWR) estimates that Arizonans consume an average of 146 gallons of water per day (ADWR, 2024).
Fruits and vegetables contain large quantities of water in proportion to their weight. When these foods are eaten, the water can be absorbed by the body. Accordingly, diet is an important part of a person’s direct daily water consumption (Table 1). Nutritionists and dieticians have often been the ones alerting people to how much water our food contains.
Fruits
Vegetables
Item
FoodWeight(g)
WaterWeight
PercentWater
Item
FoodWeight(g)
Water Weight
Percent Water
Apple
138
116
84
Broccoli
44
40
91
Apricot
106
92
86
Cabbage(green)
35
32
93
Banana
114
85
74
Cabbage (red)
35
32
92
Blueberries
145
123
85
Carrots
72
63
87
Cantaloupe
160
144
90
Cauliflower
50
46
92
Cherries
68
55
81
Celery
40
38
95
Cranberries
95
82
87
Cucumber
52
50
96
Grapes
92
75
81
Eggplant
41
38
92
Grapefruit
123
112
91
Lettuce(iceberg)
20
19
96
Orange
140
122
87
Peas(green)
72
57
79
Peach
87
76
88
Peppers(sweet)
50
46
92
Pear
166
139
84
Potato (white)
112
88
79
Pineapple
155
135
87
Radish
45
43
95
Plum
66
56
85
Spinach
28
26
92
Raspberries
123
106
87
Zucchini
65
62
95
Strawberries
149
136
92
Tomato (red)
123
115
94
Watermelon
160
146
92
Tomato(green)
123
114
93
Table 1. Water content of common fruits and vegetables.
Prepared by Sandra Bastin, Foods, and Nutrition Specialist and Kirn Henken, Extension Associate for ENRI. Information taken from Bowes & Church's Food Values. In: Water Content of Fruits and Vegetables. University of Kentucky Cooperative Extension. 1994.
Considering daily indoor use and diet, a person can develop estimates on their own personal daily water consumption and water footprint. There are numerous calculators available on-line (i.e., Water Footprint Calculator) where we can develop personalized estimates on our water footprint.
Each of us consumes a lot more water daily than our daily indoor or direct consumption. It takes water to produce all our food including fruits, vegetables, meat, bread, etc. This is true for food products that are fresh or processed. Most of the time we are oblivious to this aspect of water consumption through our food, often referred to as “virtual water”, but it represents a huge part of our personal water footprint.
It is commonly estimated that the daily diet of most people in the U.S. requires 800-1,500 gallons of water to produce (Anyabwile and Walker, 2019; Wheeler, 2022; Food Print, 2024; Michel, 2023; Smith, 2012). If this estimate is expanded to clothing, appliances, vehicles, and other items in our common daily use the average water footprint for Americans easily equals or exceeds 2,000 gallons of water per day (ASPE, 2022).
We can consider the annual Arizona population’s dietary consumptive use of water using a range of averages of 800; 1,000; and 1,500 gallons per day to support the food we eat (Table 2).
If we use an average of 1,000 gallons per day to produce the food that we eat and consider the 7.4 M Arizonans living in our state today, we can gain a good general estimate of the annual water consumption level necessary to support the population for the State of Arizona as approximately 8.3 million acre-feet (MAF).
Gallons/Day
800
1,000
1,500
Arizona Annual Water Consumption by Food (MAF)
6.6
8.3
12.4
Arizona’s statewide total direct wet water use is estimated to be about 7.1 MAF (ADWR, 2019). Considering an average of 8.3 MAF as the water requirement to produce the food to support Arizona’s population, the State is in a deficit of 3.3 MAF beyond the amount of water used by the Arizona agricultural industry, which is approximately 5 MAF (approximately 70% of the total Arizona water use).
If we consider that 2,000 gallons of water are required to support every Arizonan daily, which includes non-edible items (clothing, appliances, vehicles, etc.), Arizonans are responsible for the consumption of approximately 16.6 MAF per year.
Then of course we must also remember that the average person is directly responsible for the use of approximately 146 gallons of water per day for direct indoor use. That comes to a total of approximately 1.2 MAF per year for the Arizona population. That is much less than the reality of the total water required to produce the food we eat and support us in many facets of our life.
The main point from this discussion is that all of us in Arizona and across the nation use a lot more water than is commonly realized. Many of the food products we consume come from out of state, which is interesting in relation to the concerns being voiced regarding the use of Arizona water to produce agricultural products that are being transported to other states or nations.
We are all clearly the net beneficiaries of not only the agricultural production in this state but also from many places and other water sources beyond the boundaries of Arizona.
References:
Anyabwile, A. and S. Walker. 2019. 5 Ways to put food on a water diet. World Resources Institute. https://www.wri.org/insights/5-ways-put-food-water-diet
Arizona Department of Water Resources (ADWR). 2019. Water Your Facts. Arizona Water Facts. https://www.arizonawaterfacts.com/water-your-facts
Arizona Department of Water Resources (ADWR). 2024. Conservation. https://www.azwater.gov/conservation/public-resources
ASPE. 2022. New research shows most Americans are unaware of their daily water consumption. ASPE Pipeline. https://aspe.org/pipeline/new-research-shows-most-americans-are-unaware-of-their-daily-water-consumption/#:~:text=Most%20believe%20they%20use%20less%20than%20100%20gallons,indirectly%20%28e.g.%2C%20the%20water%20required%20to%20produce%20food%29.
Bastin, S. and K. Henken. 1994. Water Content of Fruits and Vegetables. University of Kentucky Cooperative Extension. 1994.
Food Print. 2024. The Water Footprint of Food. https://foodprint.org/issues/the-water-footprint-of-food/
Kobir. 2024. How many gallons of fresh water do we use per day. https://medium.com/rocklinca/how-many-gallons-of-freshwater-do-we-use-per-day-7987edf6b1bb
Mayo Clinic. 2022. Water: How much should you drink every day? https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256
Michel, D. 2023. Water and Food: How, When, and Why Water Imperils Global Food Security. Center for Strategic and International Studies. https://www.csis.org/analysis/water-and-food-how-when-and-why-water-imperils-global-food-security
Philadelphia City Government. 2024. Gallons Used Per Person Per Day. https://water.phila.gov/pool/files/home-water-use-ig5.pdf
Smith, T. 2012. World Water Day: How much water do you use in a day? Climate Home News. https://www.climatechangenews.com/2012/03/22/world-water-day-how-much-water-do-you-use-in-a-day/
United States Geological Survey (USGS). 2019. How much water do I use at home each day? https://www.usgs.gov/special-topics/water-science-school/science/water-qa-how-much-water-do-i-use-home-each-day
Wade, M. 2024. Where does our water wind up? Ag Alert, California Farm Bureau. 7 February 2024.
Water Footprint Food Guide and Calculator. 2024. https://watercalculator.org/water-footprint-of-food-guide/
Wheeler, M. 2022. Did You Know’ Series: How Much Water Are We Actually Using? Virginia Water Resources Research Center, Virginia Tech University. https://www.vwrrc.vt.edu/2022/03/31/did-you-know-series-how-much-water-are-we-actually-using/To contact Jeff Silvertooth go to: silver@ag.arizona.edu