How much urine, not limited to human’s, is placed in toilets versus in the wild?

Short answer: About 2.8 billion liters goes into toilets every day, and about 11.7 billion liters more goes outside.

Long answer: The first thing we need to know is the total number, or mass, of animals on earth. This helpful xkcd comic gives us a start. If you check the source for that you’ll find a list like:

Millions of Tons  Animal
0.8               Elephants
40                Horses
100               Pigs
450               Cattle
280               People
80                Whales
30                all wild vertebrates
650               all domesticated vertebrates

So what really matters are those last two lines. There are about 680 million tons of nonhuman vertebrates running around, and nearly 280 million tons of people. That’s pretty scary – mankind is a pretty big operation in the grand scheme of things, especially when you consider that the overwhelming majority of the mass of land mammals is just our livestock. I wonder what this table would have looked like a few thousand years ago; what was the total mass of animals before humans? Did we just replace the world’s megafauna, like the giant sloth, woolly rhino, and mastodons, with cattle?

Anyway, let’s do some unit conversions. The average person weighs about 60 kg and produces about 1 liter of urine a day. Provided most large mammals operate at the same urine-to-mass output, we can add up our numbers above, and get a ballpark estimate of the magnitude of piss getting dropped every day.

For animals, we’ll assume it all goes outside:

    (680 million tons)(1 liter/60 kg) = 10 281 427 100 liters

So about 10 billion liters of animal urine are getting dropped outside on the daily.

On the other hand, it seems that a large fraction of mankind doesn’t have plumbing- it’s something close to 2.6 billion people. That’s about a third of the world population. Additionally, about 700,000 children die every year due to a lack of access to sanitary water. That’s a bummer.

Anyway, humans produce

    (280 million tons)(1 liter/60 kg) = 4 233 528 790 liters

about 4.2 billion liters of urine a day, but only about 2/3rds, or 2.8 billion liters, end in toilets.

The final score is:

  1. In first place, the outside, receiving 11.7 billion liters of urine a day.
  2. In second place, the toilets, receiving 2.8 billion liters of urine a day.

These are just big numbers as far as I’m concerned – I have no sense of how big they are. Referring to a helpful Wikipage about relative volumes, I’ll see that 4.2 billion liters is a fair bit bigger than the Great Pyramid of Giza. So, humanity can piss out a Great Pee-ramid every day. Gross.



asked by /u/stackola

cover image credit: Wikimedia Commons


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