Of all the solo performers in the world, Stokley Towles might be the most civic-minded. That doesn't sound like firecracker praise, but while his colleagues use the tragedies of others as raw material—Spalding Gray on Cambodia's grotesque wartime history, Mike Daisey railing about Scientology and iPhone factories in China—Towles manages the unusual feat of finding the transcendent within superficially boring stuff.

For the past 15 years, his shows have focused on public infrastructure—waterlines, libraries, garbage, police work, a 10,000-year history of a single city block in Burien—to unearth what actually, materially connects us. By combining light anecdotes with slides and props, his work is the grown-up, performance-art equivalent of a Richard Scarry book.

Towles's latest show is a dive down the toilet bowl titled Flushed: Into the World of Wastewater Treatment. At just under an hour long, it breezes through subjects from the history of the commode (ancient Romans used communal latrines, without partitions, as meeting places) to employees at the Brightwater sewage treatment plant and their almost-parental affection for the huge community of microbial "bugs" that break down our collective effluvia. Like much of Towles's work, it both withholds and reveals information in a masterful way that leaves us with questions we'd never thought to ask.

He tells us, for example: "If you fall into one of the wastewater tanks at the treatment plant in Seattle, they'll give you a certificate that proves you are officially a member of the swim team." Hold on: Enough people fall into sewage tanks that they've designed a certificate? How dangerous is that? How deep are they? How do you get out? And then what happens? We never find out—after the swim-team detail, he abruptly shifts to a list of things found in sewage pipes.

But that is, in a way, the whole point of Towles's project—to focus our attention on, and even bring a sense of mystery to, the humdrum mechanics of our everyday lives.

Towles began to experiment with performance during graduate school at Cal Tech, where he'd initially gone to study photography. (He also briefly worked as a photojournalist.) But one of the keystone experiences that influenced his work had come years earlier, at a bus stop in Santa Cruz, where Towles approached a man he was mildly terrified of for an interview. As part of a college class project, he said, "we had to go and interview someone we imagined as far from ourselves as possible. This guy at the bus stop was totally intimidating to me, the last guy I'd approach. He was a white guy with longish hair, he moved in a strong, confident way—'thug' doesn't describe it well, but it was like: This is my block. No new people. I was afraid of him."

Over the course of three conversations, Towles learned that the man's girlfriend might be pregnant and he was deeply worried about it. "He was like nothing I assumed," Towles said. "A person just going through the world with his own stuff going on."

As trite as that might sound, the revelation had a major impact—unlike many solo performers, Towles doesn't put himself in the middle of the story. In fact, he actively tries to stay out of the way. (There's that civic-mindedness again.) The result is an understated, gentle humor that avoids verbal pyrotechnics and heavy-handed zingers.

One punch line in Flushed, for example, concerns a former garbage-truck driver named Italo who used to haul "the soup," as he called it, from time to time. (Other drivers refused, objecting to the smell.) As he was driving through downtown one hot July day, pedestrians visibly squirmed when he passed, and the driver of a convertible pulled up to yell: "You stink!"

"I must say, I agree with the driver," Towles says in Flushed. "Italo did stink. But then again, you stink, and you, and I definitely stink. That truck was filled with us, and, together, we are foul."

Towles said that working on the show—and contemplating shit on a daily basis—didn't change his relationship with food when he sat down to eat. But at one point, while his house was being remodeled, the sewer pipes had been disconnected and someone flushed the toilet, launching a little human sludge into the jobsite. Later, as workers pulled out the old pipes, Towles contemplated what those tubes had seen: the food he and his wife had cooked together, the meals he made and put in the freezer before the birth of his daughter, the romantic dinners, the birthday parties. "Our whole life has gone through these pipes," he said. "And I found it really kind of moving."