Average water use per person*day by country | Hacker News Reader

Average water use per person*day by country

data360.org

18 pointsderwiki62 comments

Most water is used for farming (grain in particular), and it would be good if it was possible to adjust the numbers based on relative import/export of food.

Countries without enough water import water in the form of grain, and vis versa for those blessed with plenty.

So don't look at this graph and automatically think "The US should reduce water use". First you have to look at how much grain the US exports.

Second you have to look at how the water is used. For example 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.

On the other hand septic systems waste water. So a county that (for household use) uses 1/4 of the water, but only uses it once is worse than a country that recycles that water 5 times on its way to the ocean. Yet they look much better on a per capita basis.

So although this graph is very very interesting it doesn't give you actionable information.

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.

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 (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.

"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.

"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.

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.

I would be very interested in seeing a breakdown of the amounts. You only drink maybe 1-2 liters per day. Showers and toilet flushes add to a fair amount but the majority has to be water for the plants and animals you eat.

At home, I think it's showers by far (something like 7 gal/minute, you do the math), ~50 gal for dishwasher or washing machine, then on down. And yea, most of the water that you "consume" is probably consumed so far upstream (hah!) that you don't even realize it.

Edit: I looked up my original source and I had misquoted dishwasher, sorry about that. The source is:

http://fi.edu/guide/schutte/howmuch.html

* Washing machines are 40-55 gal/load

* Dishwashers are 15 gal/load

* Running a faucet is 3 gal/minute

>> ~ 50 gal for dishwasher

That one shocked me especially as someone who has never owned, and never plans to own a dishwasher. I probably use around 4 litres to fill the sink and wash the dishes, at most 3 times per day - which works out at around 3.1 US Gallons/2.6 imperial gallons.

As I corrected, 15 gal/load for dishwasher. So, coupled with the fact that a running faucet is 3 gal/minute, a dishwasher is better if you leave the faucet running while hand washing dishes, and take longer than 5 minutes.

I didn't see the correction. I don't know many people who run the tap when washing the dishes. Generally I plug the sink and spend 1-2 minutes filling it with water. It still seems to work out less but I guess it depends on how ofter you fill the sink/run the dishwasher.

I used to use a huge amount of water when handwashing by rinsing under flowing water. Soap tastes icky and some screw up your digestion. Its possible you're not rinsing under flowing water.

Also consider the ratio of sink size to dishwasher size, which is a fad/style issue. My kitchen sink doing a realistic sinkful of dishes only holds perhaps 1/4 the dishes my washer holds.

It seems difficult, although not impossible, to buy a non-energy star dishwasher which means less than 6 gallons per load.

One point that everyone seems to miss is the amount of soap and biomatter being flushed thru the pipes is a constant, no matter if you handwash and use 20 gallons or use a machine and only use 5 gallons. So I donno about sewer system efficiency given an intake flow that might be 4 times more or less dilute.

I can do one dishwasher full of dishes using about 6 gallons, or about 3 to 4 sinks full, each maybe 10 gallons, for a total around 30-40 gallons. I believe this estimate to be true... in the ancient years of hand washing and old fashioned tanks, I could use up all the hot water in a 30 gallon hot water heater after thanksgiving by the end of dish time. Now that I have the tankless that will never run out, even after a handwashing thanksgiving, ironically I also now have a dishwasher which means I use practically no hot water anyway. There are other benefits to the tankless of course.

Sewers probably already have a harder time with the other major household source of solids.

Washing by hand is always worse.

> It still seems to work out less but I guess it depends on how ofter you fill the sink/run the dishwasher.

No, it's not less. It's more. A dishwasher can hold a lot more dishes than a sink.

>> " A dishwasher can hold a lot more dishes than a sink."

You put unclean dishes in the sink, wash them, take them out, and more more unclean ones in. The only limit to how many dishes you can put through the sink is how dirty the water gets which depends on how dirty the dishes are to begin with.

And no matter how good you are at it, a dishwasher does it with less water.

A modern dishwasher uses ~5 gallons:

http://www.energystar.gov/index.cfm?c=dishwash.pr_crit_dishw...

Or down to 1.5 gallons http://www.topten.eu/?page=freestanding-2

That 50 galon number is wrong. With a modern dishwasher (at least the ones sold here in Europe) you will always use less water than hand-washing, since there is massive re-circulation of the water in the dishwasher.

Do you not rinse the dishes?

It is thought (I dont know if it is true) modern dishwashers are more water efficient than hand washing. It has been repeated to me before. Might be an urban legend.

4 litres is a low estimate. Think of 4 1-litre cartons side-by-side; that's barely enough to submerge a plate. Some people may use that little water when washing up, but most use more.

The most efficient dishwashers sold in the EU use down to 6 liters per wash. http://www.topten.eu/?page=freestanding-2

Does 'at home' include watering the lawn or garden? If the drought in California is a 'mega drought' like some news outlets are saying, I hear that cities could pass laws restricting residents from watering their lawns as it accounts for up to 50% of a household's water usage [0].

[0] http://www.dailynews.com/general-news/20140125/megadrought-c...

This has happened in Australia in the past, in capital cities. You can get reported for watering your garden on the wrong days.

I'm surprised the figures for the United States vs United Kingdom are are so far apart (550 vs 150). These leads me to think much of the usage is water lost during transmission, or used in farming/industry rather than in the home.

Farming sounds very plausible:

http://www.onegreenplanet.org/news/californias-drought-whos-...

and something I never thought about: ".. humans drink less than one gallon of water per day, but a cow can drink up to 23 gallons of water a day."

Think about the sheer acreage in the USA compared to England and how much of the land is used for crops or livestock.

>> ".. humans drink less than one gallon of water per day, but a cow can drink up to 23 gallons of water a day."

They do weigh a bit more though. :) It probably ends up being ~2x-3x a human's water consumption by weight.

Rasing meat for human consumption requires a TON of water (and land)

It might also have something to do with climate. People in a warm southern US climate probably drink more water than people living in a more mild climate (UK).

Have a look at the center of the US on a satellite map and you'll see where most of our water is used.

For example, https://maps.google.com/maps?hl=en&ll=37.811411,-98.98613&sp...

(A bit east of Dodge City, KS. The circles are irrigated fields.)

Most other countries use washing machines with much less capacity and water ue (side loaders vs. top loaders), have different toilet flushing systems with smaller loads, and generally put a much higher premium on drinking water. If you compare the US to the UK, also take into account the very different climate. Due to the relatively tame and wet weather, there is almost no irrigation in the UK. Case in point: There is no place like Vegas, in the middle of the desert, with golf courses and fountains all over the place.

This is also neat:

http://environment.nationalgeographic.com/environment/freshw...

It shows how your household compares to national averages in terms of water use, diet, energy, and shopping. I was a little surprised to read that the average person does 3 loads of laundry a week. I'm closer to every 3 weeks -- but I guess I have a pretty small household.

Also consider that water is renewable. If you use less than the amount that gets replenished, you're fine. If you use more it will just get worse and worse.

Missing Canada. :(

Shouldn't the title then be "average water use per person/day by country"?

I wonder what percentage of that is from fracking.

A more important question is what percentage is used by recycling.

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