How Much Poop Does America Flush?

In my book, I claim America gives a porcelain burial to 108 million pounds of poop every single day. 4.5 million pounds an hour. 39.4 billion pounds a year.

Now I'll prove it.

Or, rather, I won't. Because my research uncovered a shocking gap in scientific knowledge: we don't actually know how much we poop.

Here's what we do know: there are 300 million Americans. In 1996, the EPA estimated that 72% of us [1] are served by America's 16,000+ publicly-owned sewage treatment plants. Assuming that number is still accurate, that's 216 million people today. Those of you who are good at math have already figured out where this is headed: 216 million people, 108 million pounds -- a daily per-capita of a half-pound of cable laid.

But that's an educated guess. Because, as it turns out, there are no definitive figures. In his book Nanomedicine, Dr. Robert A. Freitas Jr. cites three studies in putting his daily figure at 100-200 grams [2] -- that is, .22 to .44 pounds a day. A 1992 study in Gastroenterology found an average of 106 grams a day [3] among 220 UK residents, but with the caveat that "data from other populations of the world show average stool weight to vary from 72 to 470 g/day." The Merck Manual says that Westerners grunt out 100-300 grams a day [4]. But in the very next breath, Merck says that "generally, stool amount > 300 g/day is considered diarrhea" -- which is ridiculous, because who defines diarrhea by weight? A two-pound bowl-curler isn't diarrhea because it tips some arbitrary scale; nor is a sputtering blurt of rancid curry ambiguous until some formal weigh-in.

With no logical recognition of the nature of diarrhea, it's no wonder science lacks consensus on our species' blatting average. But Merck seemed pretty confident in its declaration, so for my book I split its figures -- 200 grams, .44 pounds -- and rounded up to make the math easier. Multiply by 216 million people and I got my answer. And it's a staggering figure -- the equivalent of 123 fully-loaded 747s [5]! Of 18.3 million 14-inch iBook G4s [6]! Of 108 million one-pound weights [7]!

But dive down into your toilet, swim through the sewers, and emerge at the treatment plant, and you'll discover a lot more than 108 million pounds floating through the network. Wikipedia estimates that 17% of Americans [8] are served by on-site sanitation systems like septic tanks. Septic tanks are emptied by pump trucks, and pump trucks are emptied into the sewage infrastructure -- so even those living off the sewage grid are still adding their poop to it.

(It's just too bad we can't use that poop for good [9].)

I'm sure some will question my half-pound-per-day estimate. That's fine -- I question it myself. For instance, is it even relevant to calculate a daily average? After all, while some people go three times a day, others go three times a week, and because diet and metabolism are unique to all of us, such variation in schedule is not at all abnormal. Furthermore, a high-fiber diet bumps up stool weight; those who aren't eating their veggies aren't bulking their poop. And poop itself is around 75% water -- on hot days, when we sweat a lot, does our poop weigh less?

In other words: it took me three hours to write this article. In that time, I believe America passed 13.5 million pounds of poop.

But no one really knows for sure.