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One hamburger requires 660 gallons of water to produce – the equivalent of 2 months’ worth of showers.

Per http://www.cowspiracy.com/facts/ from Catanese, Christina. “Virtual Water, Real Impacts.” Greenversations: Official Blog of the U.S. EPA. 2012. and “50 Ways to Save Your River.” Friends of the River.

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  • Explanation: That link has been thrown about a lot in pro-vegan discussions... so I am picking three of their more juicy claims more or less randomly to see how they fare.
    – David Mulder
    Nov 27, 2014 at 18:11
  • They source it to the official U.S. EPA. If that source does not convince you, what would?
    – gerrit
    Nov 27, 2014 at 20:08
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    @gerrit: Well, according to one set of estimates I found you can in theory make 1400 hamburgers from a single cow, that would thus mean 3500000 liter is needed to raise a cow. That's a lot. Not saying it's impossible, but it's enough for me to be quite skeptical.
    – David Mulder
    Nov 28, 2014 at 0:50
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    @DavidMulder it actually seems to work out - if local farmers can feed (rough estimate but reasonable) about two cows per hectare, my local precipitation is ~700mm/year and it takes a year and a half before they're slaughtered, then the share of rainwater that each cow 'consumes' through its grass would be about 5000 tons.
    – Peteris
    Dec 2, 2014 at 5:05
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    @Peteris Except a lot of water isn't 'used' by the grass and goes right through... which is then for example pumped up to be used by humans or more likely ends up in a local stream or river.
    – David Mulder
    Dec 2, 2014 at 7:16

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I'm going to assume a quarter pound (113 g) burger with no cheese or other added feature. This being the case the bread can be neglected as the water-cost of beef is going to dominate. I'm also assuming that the unit of volume being used is the American gallon and not the imperial gallon.

The answer is definitely going to depend upon how you raise the livestock as grass-feeding requires much less water than grain-feeding. That being said there is research out there on this. Estimates vary quite widely as you might expect given the in-built problem of how the cattle are farmed. The results per burger (to the nearest whole number):

  • 111 gallons (418 litre)[1]
  • 480 gallons (1816 litres)[2]
  • 405 gallons (1534 litres)[3]
  • 621 gallons (2352 litres)[4]
  • 616 gallons (2331 litre)[5].

[2] is a global average estimate, [1], [3] and [5] are based on American data and [4] is based on Japanese data.

So, although I'm not sure where the number 660 gallons (~2500 litre) is coming from, it appears to be in a believable range. Taking an average of these numbers gives you 447 gallons (1690 litres). The vegan sites' estimate is close to the upper values of this group of studies. Maybe a bit high.

According to Waterwise[6] (a UK-based NGO dedicated to water efficiency and conservation) a normal shower uses 2.05 American gallons/minute (7.75 litres/minute) and a power shower uses 4.49 American gallons/minute (17 litres/minute). Using their 660 gallons estimate, in an average month (30.42 days) of once daily showering, if you use a power shower and you have a shower for less than 4.83 minutes, you use less water than when you eat a hamburger. If you use a normal shower you can enjoy rather longer daily ablutions; anything less than 10.58 minutes will mean you have used less water than eating a hamburger. For 2 months half those times. I suppose it is plausible to have a daily 5 minutes with a normal shower. That would mean using less water use in 2 months of showering than in eating a hamburger.

[1] Beckett, J. L., and J. W. Oltjen. (1993) 'Estimation of the water requirement for beef production in the United States.'

The model estimates 3,682 L of developed water per kilogram of boneless meat for beef cattle production in the United States.

[2] Chapagain, A.K. and A.Y. Hoekstra (2003) ‘Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products’

Table 4.4 says the world average of Virtual water content is 15206 m3 /ton) for

Bovine meat and meat offal not else specified, excluding livers, prepared or preserved

[3] Zimmer, D. and Renault, D. (2003) ‘Virtual water in food production and global trade: Review of methodological issues and preliminary results’ (section 5)

[4] Oki, T.; Sato, M.; Kawamura, A.; Miyake, M.; Kanae, S., and Musiake, K. (2003) 'Virtual water trade to Japan and in the world' (section 15):

[5] Kreith, M. (1991) 'Water inputs in California food production'

[6] Water Wise

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  • This is my first attempt to answer a question on Skeptics.SE and I'd appreciate feedback especially if this is not a good way to do it.
    – Reluctant_Linux_User
    Nov 28, 2014 at 18:02
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    Feedback: links to sources are a big plus because it's way easier to verify. Quotes from sources showing results and/or methodology is good too. Good first answer!
    – William Grobman
    Nov 28, 2014 at 18:10
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    It might be a bit silly, but you should probably go into similar metrics about showering. Showering is probably at least as problematic a metric to determine.
    – DampeS8N
    Dec 1, 2014 at 18:34
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    So I have made a huge error as a non-US person on the definition of the American gallon and I am very sorry. I have now corrected this. Additionally included information on showers and given links to open-access sources for this information. The methodologies are not altogether straightword. I'd advise anyone interested to read the papers.
    – Reluctant_Linux_User
    Dec 2, 2014 at 12:07
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    Really great answer! I do hope you'll stick around and contribute more; we can always use more answers of this quality.
    – William Grobman
    Dec 2, 2014 at 13:53

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