Where is all the water going?

A primer for understanding agricultural water usage with a focus on beef

Water use or water borrowing?

Headlines and memes about water use abound. With all this water being “used,” it’s a wonder the earth has any left. Should we be concerned? Researchers at the Natural History Museum of Denmark say not to worry. By studying isotopes of water, they found evidence that earth’s oceans contained significantly more water in the deep past, which has since been lost to space. However, this process is measurable only over geologic time, and occurs so slowly as to be inconsequential to humans. Our problem with water isn’t that there is less overall, it’s with where our water is located, as glaciers melt and become seawater, and aquifers are depleted for human use. In agriculture, the issue isn’t always total used, but where that water came from, and the amount of pollution we add as it passes through farms.

I often see high water usage mentioned as a reason to cut down on meat eating, with typical claims of a pound of chicken needing 500 gallons for production and a similar amount of pork needing 700 gallons. Supposedly, a whopping 1800 gallons is used to produce a pound of beef. Should we take these figures seriously? What is meant when we say food production “uses” water? In this piece, I’ll focus on beef since it is usually pointed to as the absolute worst in terms of water usage.

When I vacuum my floors (a rare occurrence!) I use electricity which has been generated by burning coal, then delivered to my house via power lines. The electricity that powered the Electrolux is now gone, and I can’t use it again. Same with the natural gas that we burn for heat and cooking. Water is slightly different: I pay for the privilege of having water purified to potability, and pumped through underground pipes to our house for showers, dishwashing, coffee making, etc. After use, it goes down the drain, but it isn't gone. It re-enters the water cycle and will be available again for human use, or to hydrate plants, fill lakes and streams, to evaporate and return as rain, and myriad other possible paths.

Even though water differs from other resources, as explained above, facts and figures about its usage are often shared with no explanations. We are supposed to assume without question that a steak or pork chop represents a hugely wasteful agricultural process, and that we can “save” water by choosing an alternative meal.

The green, the blue, and the gray

To understand what is meant by statements about agricultural water use, it helps to be familiar with the following terms:

Green water … is water from precipitation that is stored in the root zone of the soil and evaporated, transpired or incorporated by plants. It is particularly relevant for agricultural, horticultural and forestry products.

Blue water … 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. Irrigated agriculture, industry and domestic water use can each have a blue water footprint.

Grey water … is the amount of fresh water required to assimilate pollutants to meet specific water quality standards. The grey water footprint considers point-source pollution discharged to a freshwater resource directly through a pipe or indirectly through runoff or leaching from the soil, impervious surfaces, or other diffuse sources.

(Courtesy of Water Footprint Network https://www.waterfootprint.org/water-footprint-2/what-is-a-water-footprint/)

Considering the gray water footprint

The fact that the concept of a gray water footprint exists is heartening; it names something that many people may not be aware of, i.e. the amount of water needed to dilute agricultural run-off and point source effluent to certain standards. Judging from the dead zone in the gulf of Mexico and elsewhere, and the growing presence of agricultural chemicals such as glyphosate in surface water, we should be very concerned about gray water. Perhaps at one time the solution to pollution was dilution, but this isn’t working any longer. Polluted water may very well be diluted to legal standards locally, but on a wider scale the strategy is failing.

Location — or, more accurately, setting — plays a large role in gray water footprints. It is a major issue where large numbers of animals are confined and feed crops are heavily treated with chemicals. Fortunately, reduction of the gray water portion of meat’s footprint can be achieved by consuming pasture-raised animals from farms that do not rely on finishing with corn, soy, or other heavily chemicalized feed crops.

When animals are raised on pasture under conditions that mimic natural lifestyles, their manure nourishes soil rather than becoming pollution. It feeds microbial life and fertilizes the plants that will eventually be consumed. Nutrients are cycled rather than sequestered or flushed into surface water, and the need for fertilizers and herbicides is reduced or eliminated.

Raising and finishing animals on pasture rather than confined in feedlots or factory farms is often criticized as being less efficient. Gray water represents a problematic outsourcing of the job of cleaning up agricultural pollution to rivers and streams. To achieve a true accounting of the efficiency of any system, externalized costs such as this must be taken into account.

Green versus blue water

Gray water is a critical aspect of a water footprint, but it comes into play at the end of the agricultural process. It is green water and blue that provide for animals daily drinking needs and produce feed crops. These two types of water have been separated for ease of understanding human water usage, but it’s important to remember that in the real world, rain, ground water, and surface water all interact, and there are no hard boundaries among them. Water is green while falling as rain, and blue when it hits the surface of a lake. The important distinction between the two for water usage considerations, is that green water is largely labor-free as far as humans are concerned, whereas blue water needs energy to be pumped and piped, and requires significant infrastructure. Also, blue water coming from aquifers is often a finite resource that will not be replaced.

Common ways to illustrate the water needed to produce a pound of beef include comparing it to 39 bathtubs filled to the top, 99 eight-minute showers, and 350 loads of laundry. Whoever came up with these comparisons might not have intended to mislead anyone, but their choice of examples is deceptive. These cleansing activities almost always use exclusively blue water, whereas raising beef cattle, at least in certain areas, relies mainly on green.

Though laundry and bathing don’t necessarily require potable water, our homes and water systems are designed to use it for everything. Unless you have a well, you’re using water with a high level of embedded energy, which is often costly and rightly so. When expensive showers and laundry loads are used to illustrate water needs for livestock, we’re being not so subtly manipulated to believe cattle require blue water and use it exclusively.

As a hobby farmer, I’m no expert on meat production, but I do have a little knowledge of the feed and water needs of livestock. When I read that 1 lb. of beef equals 1800 gallons of water used, I think of my horses and how much water they have consumed in their years here (about 30 horse-years if taken together). You might think that providing water for horses for so many years has added up, but in fact they’ve barely used any at all. Rain collection barrels and stock tanks fed by the roof of house and barn hold enough water for the needs of the animals in all but the worst droughts and deepest freezes. This water is green water that is briefly intercepted on its way to the ground.

Some city (blue) water was needed to get us through this summer’s drought, and most winters bring temps low enough to freeze the winter tank solid for a week or two, necessitating carrying buckets from the house. However, this tap water is really just borrowed. It is sourced from a river, and falls to the ground as horse urine, fertilizes the pasture, and returns to the water cycle. To fully understand cost of this water, an accounting of energy used by the local water company to purify and deliver it should be made, but the water itself is not truly “used.”

The significance of irrigation

Of course, most cattle, swine, and chickens aren’t raised as my animals are, and their water needs are met in different ways. Also important: Water use calculations for livestock must include not only drinking water, but water used to produce feed. In arid regions, water used to irrigate hay and grain crops represents a significant portion of the water footprint. The image below from the USDA gives an idea of where crop irrigation occurs in the U.S.

It’s no coincidence that most irrigation is carried out in the western half of the country. The 100th meridian (shown below) is the line that roughly divides the country into the arid West and the humid East. Crops grown successfully in the Northeast without supplemental water are possible in many areas of the West only with irrigation.

In the irrigation illustration, the large cluster of blue dots in Nebraska is mainly a result of the presence of the Ogallala Aquifer, which lies under much of the state and has been tapped for large-scale irrigation since the 1940’s. Also notable is the absence of blue dots in much of the East, where irrigation isn’t necessary. As we will see, location is a major factor in blue water footprints, though this is rarely explained when a number like 1800 gallons is attached to a pound of beef.

Horses aren't cattle, but both consume grass and hay, and are large animals with relatively high water needs. I’ve been able to take care of my horses using green water almost exclusively, a claim I extend to feed production as well as drinking water. As shown in the map above, from the Carolinas north, irrigation is rare is the East. Even though droughts aren’t uncommon, expensive irrigation installations aren’t cost effective because most years a decent crop is produced with rainfall only. Same for fertizer: It’s more common to spread manure to maintain fertility than to apply costly synthetic products. Consequently, blue and gray water form a small portion of the water footprint.

Ask a farmer

If I were raising cattle rather than horses, there would be further blue water needs associated with butchering, but this is a very small part of total water needs. I’m pretty confident in my claim that it is possible in humid parts of the country to raise beeves whose water needs are met almost exclusively by rainwater, using far less than 1800 gallons per pound. To check if my belief could be corroborated, I reached out to my beef farmers to see if they agreed. They kindly pulled out their calculators and crunched some numbers.

Based on a two year lifespan, and accounting for the fact that a 1100 lb live steer produces 363 lbs of take-home meat, they came up with 20 gallons of water needed per pound of beef. There are several reasons this is remarkable, beyond the obvious one that their figure is far less than the 1800 gallons usually reported. One is the ease at which this wife/husband team arrived at this amount. They had no trouble with the numbers they needed for input because they are intimately involved in all aspects of their operation. They know their cattle and what it takes to bring a pound of meat to market.

The other notable and very interesting detail is that apparently they have never before had to perform these calculations. Because they are raising cattle in an area of relatively high rainfall, nature can be counted on to provide adequate moisture. In their words,

Our cattle primarily drink water from creeks and springs. We have two paddocks that rely at least in part, on our well water. We get the bulk of our hay from our neighbor, and he does not water his hayfields. We don't know anyone who does.

This was a hard year because of the drought that affected much of the eastern U.S. Creeks dried up and these farmers made use of well water to a greater degree than usual. However, nearly all of the water their cattle used was either green water, or blue water from wells that will be replenished naturally.

The worst case scenario

It’s pretty clear that whoever came up with the figure 1800 gal/lb didn't talk to these farmers. Since I haven’t yet found the original source for this number, nor an explanation for how it was calculated, I’m going to make the assumption that it represents not only the worst case scenario, but counts rainfall as equal to water pumped from lakes and wells.

If I was searching for the area that uses the most water, it would be a dry region where feed crops must be irrigated, and the gray water portion is elevated due to high chemical use. In the United Ststes, much of the western half matches this description. While every state in the union contributes to cattle production, most operations are clustered right around the 100th meridian, as illustrated below. Enormous feedlots are common, where animals are finished on water intensive corn and soy products. Cattle in such areas spread their manure on pasture for the first part of their lives, but once the move to feedlots is made, their waste is held in lagoons. Water is required to flush manure out of cattle lots to the lagoons, and to dilute and treat the sludge that results.

(Map coutesy of Data Pandas https://www.datapandas.org/ranking/beef-production-by-state)

This High Plains region receives significantly less rainfall than the eastern U.S., but has lots of open land, much of which lies above the Ogallala Aquifer. This reservoir of underground water created millions of years ago provides for the needs of people who live in the region, and makes agriculture as it is practiced there possible. It is pumped for livestock drinking water and to irrigate feed crops. There’s a big problem however: Water that is taken is not replaced.

While not all agricultural operations in the West deplete aquifers, the plight of the Ogallala shows that it is not enough to distinguish between green and blue water (though this would be a good first step!) We also need to acknowledge the difference between blue water that is replenished and that which, once pumped out, is not recharged, since the environmental effects differ greatly between the two.

Toward a more transparent footprint

The image of 39 bathtub’s worth of water going down the drain to produce the meat for your family’s dinner creates the idea that this water is lost. The water isn’t gone, although it may have been removed from an aquifer or polluted in the process of animal production. If neither occurred, and it was merely briefly intercepted in its cycle as green water is, how should it included in the footprint? Was it used in an arid region where taking it for raising beef meant less water available for wild creatures or human drinking water? Or did it come from a plentiful creek or well where its extraction had little effect?

Analyzing water use as blue, green, or gray can be useful, but only if we know the actual breakdown for the beef we consume. And reality is much more complicated that this system implies. An analysis of beef’s water footprint that I could respect would include a breakdown of the contribution of green, blue, and gray water, an explanation of irrigation sources like wells, aquifers, and surface water, plus information on how footprints differ based on location.

With almost infinite information at our fingertips these days, answering questions about water use should be simple. I haven't found this to be the case. Rather than good analysis of agricultural footprints, I've found the same numbers repeated over and over with little explanation. It seems to me that most articles available online that present the enormous amount of water needed for beef production weren't written for the purpose of educating readers about water use, but simply to get people to stop eating beef.

The best way to discover the water footprint of the food you eat is to investigate for yourself. If you are consuming beef of unknown origin, it will be impossible to find its true footprint. The only sure way to know what goes into food production is to source it locally and ask questions of those who produce it. This means finding farmers and talking to them. I suggest heading to the local farmers’ market. You might get your ears talked off, but the knowledge gained will be well worth it.