Would You Drink Water that Used To Be in Your Toilet?

  • In a recent study, about half of Americans said they would at least try drinking treated wastewater. Photo: Lou Blouin

March 27, 2015

Recycling wastewater into drinking water is an idea that’s gaining traction as more places around the world face water shortages. Earlier this year, Bill Gates caused a media flurry when he raised a glass of treated toilet water to his lips. The photo-op was used to demonstrate a Gates-funded machine—the OmniProcessor—which turns sewage water into potable water and electricity. But many people remain squeamish about drinking water that was once in their toilets. That’s not surprising to Paul Rozin, a professor of psychology at the University of Pennsylvania. He’s recently published a study about Americans’ attitudes about “recycled” water. The study found that 49 percent of people surveyed would try treated wastewater. But 13 percent said they wouldn't, under any circumstances. Recently, we talked with Professor Rozin about the findings. Here are some highlights from the interview.

On how all water we drink is “recycled”

“Well, I think we are blissfully ignorant about where our water comes from. Basically, there’s a hydrological cycle: The water comes out of your faucet or toilet, it gets processed somewhat, it gets dumped into something like a river or an ocean, it evaporates, eventually comes down as rain into a stream and into a water body, where it goes back into the cycle. So all our water is toilet water, but not just half an hour ago. ‘Toilet-to-tap’ is the motto of the people who oppose this, and they’re absolutely right: This is a fast exchange, but everything’s toilet to tap. One of my colleagues calculated that if you live in Europe, and drink a glass of water, you’re going to get a few molecules that passed through Adolf Hitler. Now it isn’t true in the United States yet because it takes 2000 years for water to equilibrate, not counting the water in glaciers. So you’re drinking Moses water. But my point is all water is contaminated by its past.”

On the “gross-out” factor

"If you’re sitting on a train and somebody you don’t know is sitting next to you, and you open your mouth and they breathe into it, that would be very unpleasant, right? But in fact, they’re sitting next to you and breathing air out and you’re breathing air in. That doesn’t bother you, but you don’t think about that. All sorts of things in our world are sort of contaminated. Every doorknob in a public place has been handled by many people, and we're just not thinking about it. We get used to it. What’s odd about this is that it’s a new publicized form of a linkage between something we do and something that’s disgusting. Eventually, we would get used to it. The problem is getting it started. One way to start it is to have them do everything but drink it. So suppose you use it in your shower, and you use it for cooking, but you didn’t drink it—you got bottled water. After a while, it would just be a nuisance, and you’ll say, Well, I’ll just drink it from the faucet."

VIDEO: Watch Bill Gates drink water that was sewage 10 minutes ago


On the psychology of “contamination”

The way we do it, in the laboratory, is we take a dead cockroach and drop it in a glass of water and take it out. And nobody will drink it. And we say, why not? And they say, because typically cockroaches are disease vectors, who knows what I’ll get from the water? So we do it again with a sterilized cockroach, and they still don’t want to drink it. Because there’s some sense that cockroach has entered the juice—the juice has been "cockroached." And so we don’t want to wear clothing of other people or other people we don’t like. We don’t want anything that we find disgusting to touch anything else. That’s a very basic thing. It’s probably part of our biology, because generally speaking, something that’s infectious, like a cockroach or feces, is something that you shouldn’t have anything that contacts it. That’s perfectly reasonable. But not after it’s sterilized. We call it spiritual contagion. It’s just a sense that something leaks out of an object, even if it’s not a physical thing. It gets into water it touched. The water, by the way, is fine. It’s not a question of what’s in the water; it’s a question of the history of the water.

Has he tasted it?

Oh yeah. It’s actually purer than most of the water that we drink. It’s pushed through a membrane that only lets molecules the size of water or smaller go through. And water’s a very small molecule.