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Check this out, from the EPA: http://i.imgur.com/3S4LnzS.png

Can that be true? Why does generating electricity use more water than farming?

http://www.epa.gov/watersense/our_water/water_use_today.html

> Running an average refrigerator all day uses about as much water as a ten-minute shower

http://www.scientificamerican.com/article/how-saving-energy-...

Electricity generation uses a lot of water, but it's generally not used up by electricity generation. AKA, dams take all the water from a river but a river can have 6 dams and still have significant flow, because the only real loss is evaporation. Farms on the other hand evaporate most of the water they use.

You need the water for cooling in a power plant, this is why many are built near rivers or lakes, and if they aren't they will have large manmade ponds or lakes from which to gather and dump water.

http://www.world-nuclear.org/info/Current-and-Future-Generat...

> Why does generating electricity use more water than farming?

It uses it in the sense that water touches the machinery. But it doesn't use it in the sense of the water not being available anymore.

The water is used for cooling, but it's put right back in the river it came from and can be used again by another power plant, or for drinking water.

"Most water is used for farming"

And most farming is for animal feed which is wasteful compared to consuming far less meat. We could reduce water usage significantly by reducing meat consumption. We should probably do this.

In Australia, the two greatest waterhogs - the ones causing strain on water supply - are cotton and rice. We have a sizeable beef industry. That beef is not eating cotton and rice.

Are you importing feed?

No, but we do a lot of grazing. The internals of Australia isn't all desert.

The vast majority of beef production does not use grazing.

You might want to stick a 'solely' in there, because it's plain not true that the majority of beef production does not use grazing. Most beef production raises on grass and 'finishes' on grain, and there are lots of different grades. Some beef is raised on little but grain. It varies heavily on location and climate.

My main point stands. If you want to dramatically reduce your impact on water use, consume less meat.

And wear less cotton, eat less wheat, sugar, fruits and rice.

You are arguing for the sake of arguing, and making bad arguments as a result. If you eat vegetables instead of beef you will save a lot of water. You will get the same amount of food, with far less water use.

"The Agriculture industry consumed 6,987 GL of water in 2009–10. Sheep, beef cattle and grain farming had the highest consumption within the Agriculture industry,"

http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/...

Also

http://www.grub.com.au/News/FoodFacts/post/2013/02/06/In-Aus...

Sheep, beef cattle and grain farming

Unsurprisingly, when you concatenate these three things together, including both wool farming and wheat, two of the country's major exports, it does rise higher than cotton farming. It's like saying if you put the US, Mexico, and Brazil together, they're bigger than Canada.

Also, from your second link: To understand what’s going on we need to look more closely at the numbers.There are currently about 720,000 head of cattle in Australia’s feedlots, out of a national cattle herd of 28.5 million. This represents about 3%. So, however you look at it, the vast majority of cattle in Australia are grass-fed. <- This is the finishing I was talking about earlier, and the statement that the vast majority of beef doesn't use grazing is wrong.

"Most water is used for farming (grain in particular)"

True, but how do you know they didn't already make that adjustment? I can't find any reference in the original report.

"household water usage with a sewer system is a null usage. Reducing that does almost nothing - all the water used gets recycled downstream by the next city downriver"

Except in Seattle, San Francisco, New York, Los Angeles, and many other coastal cities, where the sewage outfall is in the ocean....

"...septic systems waste water."

Functioning septic systems don't store water. They drain it to a field, and it goes wherever any other form of runoff would go. I don't see how you arrive at the conclusion that this is "wasteful".

> Except .. coastal cities, where the sewage outfall is in the ocean....

That is true, and it's an opportunity. That water should be captured for farm use. However by the time the water got to those cites it has (hopefully) been used many times.

> Functioning septic systems don't store water. They drain it to a field, and it goes wherever any other form of runoff would go. I don't see how you arrive at the conclusion that this is "wasteful".

Because no one can drink this water. Obviously on a global level water can't ever be wasted. So talking about water waste must necessarily be about available water. Runoff is a waste in that sense.

I thought so too. US is world's largest exporter of grains. http://www.reuters.com/article/2008/08/05/us-russia-agricult...

So explain Spain. They have massive farming operations in a rather dry area and yet use significantly less water than the US. A significant portion of the vegetables and fruits in any grocery store here in Germany come from Spain.

Every square meter of Spain could be farmland and the United States would still have 3.5x as much farmland (that is, Spain's total landarea is less than a third of the United State's cropland).

As it stands, the United States has about an order of magnitude more cropland than Spain[1].

[1] http://www.wolframalpha.com/input/?i=farmland+in+united+stat...

You'd need to look at farmland per capita to interpret the original numbers, not just total farmland.

Not sure that's fair if the United States is exporting a larger percentage of it's agriculture (as in, that water is indirectly being consumed by other nations). So we'd need to account for who exports / imports from each nation.

Regardless, the United States has 1.4x as much cropland per capita, which already accounts for a good portion of the 1.8x increase in water usage per capita.

Spain doesn't get heavy snow across the half of it every year. The US does get a hell of a lot of water falling on it.

Water usage should also imply that the water used is not reclaimable. For example, steam from a hydroelectric plant falls back as precipitation. Irrigation water re-enters the water table or streams. For water to be used in a way that is negatively impacting it must be converted to a chemical that won't naturally degrade to water. For example, urine, ozone, etc.

Urine and ozone both rapidly decompose.

A considerable amount of the U.S. agricultural use is in the central, plains states, a.k.a. "the Great American Desert". There, agricultural water use rates are significantly greater than the rate of replacement.

> Most water is used for farming (grain in particular)

Is artificial irrigation used for growing grain in the US in any meaningful amount? Rain falling on crops shouldn't count towards "water usage", since the rain would just fall on other plants (e.g., grass or trees) in absence of farming.

Table 32 here breaks it down:

http://www.agcensus.usda.gov/Publications/2007/Full_Report/V...

There is substantial irrigation of grains but the majority of grain acres are not irrigated.