2,500 gallons of water are needed to produce 1 pound of beef. Cowspiracy
Waterfootprint.org has some great stats and scholarly sources for this information. Their statistic is that 15,415 litres of water are required to produce one kilogram of beef, which works out as about 1850 US gallons per pound.
Most of the total volume of water (98%) refers to the water footprint of the feed for the animals. Drinking water for the animals, service water and feed mixing water account only for 1.1%, 0.8% and 0.03%, respectively.
Their primary source is Mekonnen and Hoekstra (2010)
The statistic above citing water usage is relatively meaningless without the context of what the alternative consumes. Fortunately the Waterfootprint.org article allows us to contrast on a litre-to-calorie basis, which shows that cereals (e.g. wheat, oats, barley, etc.) require 0.51 litres per kilocalorie in contrast to beef’s 10.19, and chicken’s 3 litres.
Grass fed meat
As the statistic above shows the vast majority of the water consumption for animal products comes from producing the feed, carnists will often try to discredit it on the basis that it does not apply as ‘water consumption’ when animals are eating grass on naturally occuring plains.
The rebuttal from Eishel, Gordon, et al. is worth quoting here.
A possible objection to the [conclusion that beef uses 160x more land than potatoes/wheat/rice] is that beef production partly relies on pastureland in the arid west[ern United States], land that is largely unfit for any other cultivation form. [… T]he objection ignores other societal benefits those arid lands may provide, notably ecosystem services and biodiversity. It further ignores the ≈0.16 million km2 of high-quality cropland used for grazing and the ≈0.46 million km2 of grazing land [..] that can thus be diverted to food production. Even when focusing only on agricultural land, beef still towers over the other categories. This can be seen by excluding pasture resources and summing only crops and processed roughage (mostly hay and silage, whose production claims prime agricultural land that can be hypothetically diverted to other crops). After this exclusion, 1 Mcal of beef still requires ≈15 m2 land (Fig. 2A), about twofold higher than the second least-efficient [animal product] category.
In simpler terms:
- Even if you exclude the land the cattle grazes on it uses 15 square metres of land per thousand calories to raise beef due to the harvested hay and silage (compacted grass feed).
- Removing the cattle from the pastureland would promote biodiversity even if it was unsuitable for growing crops.
- There are 0.62 million square kilometeres (which is slightly larger than then entirety of France) of pastureland that are suitable for crops in the United States.
- We don’t need beef, or any other animal products to shore up our calorie or protein intake, as acre for acre plants are on average 100 to 160 times more efficient.
The stats from the quote cite land usage, but the argument stands (though the numbers differ) for water usage.
- Eishel, Gordon, et al. “Land, irrigation water, greenhouse gas, reactive nitrogen burdens of meat, eggs and dairy production in the United States”. Proceedings of the National Academy of Sciences. Vol. 111 No. 33 June 2014 and the Referenced Supporting Information Sheet, and the Dataset S1 Excel Spreadsheet
- Mekonnen and Hoekstra (2010)