Do you know which bathroom stall is (almost always) the cleanest?

December 24, 2021

Some of us gleaned the knowledge from a germophobic parent. Others learned it from a glossy teen magazine. One person said she might be making up the memory of learning it at all, although she somehow follows the protocol religiously. The secret? That the first bathroom stall is the least popular—and thus the cleanest, reports Slate.

But the less-bathroom-savvy among us may be wasting brain space on The Great Stall Choice. Maybe the first stall seems too obvious, they think, so better go for another one. Sometimes, on a whim, they head to the far end,or gravitate to the middle stall.

More than a few, however, are unburdened by this daily decision-making process. These first-stall devotees are part of what is effectively a private club—though a less exclusive one than its members would hope. As it turns out, first-stall hearsay has been making the rounds over the past few decades.

Leigh, a consultant in San Francisco, recently told Slate, “I really thought it was this life hack that only I had.” She’s been a first-stall user since high school.

“Every time that I’m in the first stall and that it’s clean, I feel a little tiny celebration,” she said. “I just feel so happy that I cracked this code and had this lesson early on in my life.” (And it was indeed a lesson—the information was on a poster in or the chalkboard of a high-school math teacher.)

Leigh’s sentiment was shared by a number of  members of Slate’s editorial team, who, like her, were recently unsettled to discover their “secret” lies somewhere between actual secret and, as Leigh put it, “universal truth.”

First-stall users range from dogmatic to casual. Leigh, for instance, always chooses the first stall unless it turns out to be unclean.

Slate writer Christina Cauterucci also strictly follows first-stall advice, which she learned from her mother a decade or two ago, with three notable exceptions: When “it’s visibly gross, it’s a handicap-accessible stall, or there’s someone in the stall next to it, in which case I’ll pick a stall with at least a one-stall buffer between me and that person if possible,” she said.

The buffer is an important exception—one that others, such as Slate writer Molly Olmstead, adhere to, even when it means walking farther. As Molly said, “My sweet spot is the intersection of laziness and personal space.”

Former Slate writer Ruth Graham heard the advice as a preteen. (Ruth is now at the The New York Times.) She’s less regimented and said she probably chooses the first stall “more than half the time.”

June Thomas, a Slate Podcasts producer, is similarly uncommitted. (She’s a first-stall user, but of the rare variety that hadn’t heard the claim.) “I like to think I let my intuition guide me,” June said, “but chances are it always leads me to the first stall.”

It’s unclear whether the claim holds up, although researchers do estimate that the middle and farthest stalls get the most traffic. It’s not uncommon to see warnings to avoid the middle stall at all costs. This line of reasoning is based on what psychologists call centrality preference,” which posits that people prefer the middle option when presented with similar options.

1995 study, which analyzed toilet paper usage over a ten-week period in a public restroom in California, supports this argument: Sixty percent of the finished rolls were from the four-stall bathroom’s two middle stalls, while 40% came from the end stalls.

However, other research shows that women, in particular, gravitate toward stalls farther from the door. This could be because they’ve assumed, like Isabella, a curator in São Paulo who has used the farthest stall since she was 14, that “fewer people would make the effort to go the distance.”

But it more likely has do with privacy and the fact that U.S. bathroom stall doors often have gaps at the sides.

Indeed, the vague suspicion of a privacy factor is perhaps the most important piece of evidence supporting claims about first-stall cleanliness. Philip Tierno, a professor in the Department of Pathology at New York University, told The Healthy in 2019, “It’s true that if you take a survey … people tend to (subconsciously or not) go to the stalls that are in the more sequestered section of the bathroom, and avoid those up front.”

What’s missing from this analysis, as you’ve probably noticed, is men. It’s perhaps too gender-normative to conclude that men simply care less and leave it at that. So we talked with a few male friends, all of whom were too embarrassed to attach their names to this highly scientific endeavor. None cared about germs or stalls with the most foot traffic. For the most part, they were surprised to hear that people even think about this, though one did mention that he never chooses a stall adjacent to another person and prefers stalls near a wall (again: privacy).

Another admitted he has a “slight bias” for the first stall due to convenience; he also brought up urinal etiquette—choose the far end, space yourself out with gaps in between—but said that it doesn’t extend to stall use: “Stalls are stalls! They have the highest level of privacy afforded already!”

The verdict? The first stall is probably still your safest bet if the least germy toilet is important to you and you’re in a women’s bathroom. That is, until people see this article.

Research contact: @Slate