Nearly a century ago, a plumber installed a toilet in a bungalow in south Minneapolis.

When the job was done, the workman took a pencil and signed his work on the inside of the toilet tank lid in a flowing cursive hand: "Otto Johnson plumber May 6, 1924."

And why not? A good craftsman is proud of his work, and indoor plumbing was still kind of a big deal back then.

It may have been the first indoor toilet to have been installed in the 1910 house in the Ericsson neighborhood near Lake Hiawatha, said the current homeowner, Alan Peters. Peters believed the original residents may have been using an outhouse before then.

Peters and his wife, Penny Marsala, bought the house in 1987, and he discovered Otto Johnson's signature when he had to take off the toilet tank lid to do a minor repair on the flapper valve.

"I was amazed to witness the pride in craftsmanship that Otto demonstrated. I felt privileged to have benefited from his work, done well and with care, so many years before," Peters said.

Respect and admiration

Over the years, Peters said, he would sometimes show the signed toilet to other workmen who came to the house.

"They all marveled at his inscription, smiled and understood," Peters said. "Some took pictures of Otto's message to share with others."

In December, Peters retired as the founder of Can Do Canines, a New Hope nonprofit started in 1989 to provide service dogs for people with disabilities. He and his wife decided to move to Pennsylvania to be closer to children and grandchildren.

Before they put their Minneapolis home on the market this spring, real estate agents advised them to replace the old-fashioned toilet with the tank that hung on the wall.

"I felt kind of guilty for taking it down before the 100th anniversary," Peters said of the plumbing fixture that had performed faithfully for so long. And he couldn't bring himself to throw away the proof that plumber Otto Johnson was a craftsman who stood by his work.

"I could not in good conscience take this evidence of pride to throw out in the trash," Peters said.

Amateur sleuths solve the mystery

He asked for help on the neighborhood social media site: Did anyone know of descendants of the plumber Otto Johnson who might be interested in "something that might be of value" that he discovered in the toilet?

Within hours, the internet started doing its thing. Armchair researchers started reporting their findings from old city directories, grave and ancestry websites, historical society records and collections of old building permits in an extensive thread of comments on the Nextdoor site.

"They built on each other," Peters said.

After all, people are fascinated by quirky discoveries hiding in old homes. There's even a Facebook group called "Things Found in Walls — And Other Hidden Findings" about the weird stuff — shoes, old newspapers, toys, bottles of booze, even money — that people find hiding inside walls, crawlspaces, basements, attics and garages.

The Facebook group was started in June 2019 by Amanda Gore and Laura Kemp of Everett, Wash. During the pandemic, membership ballooned to more than half a million people worldwide as lots of people remodeled their homes.

Homeowners would find stuff from the past, some even deciding to hide time capsule artifacts of their own for future discoverers.

"There's an element of mystery and history that combine when people find something in their house or yard," Kemp said.

Peters said the amateur sleuths looking for his plumber ran into a few dead ends, possibly because in the early 20th century, there were quite a few people named Otto and Johnson living in the Twin Cities, and even more than one plumber named Otto Johnson.

Minneapolis resident Anna Reding helped with the research by looking at old Minneapolis city directories available online from the Hennepin County Library system.

St. Paul resident Jim Willenbring contributed information he found by looking at census records, the website and an old Star Tribune obituary.

"I got intrigued," Willenbring said. "You just get this really warm feeling knowing the impact your ancestors have had in this world."

"Nextdoor can sometimes be an antagonistic and divisive place. It was nice to see it can be happy and helpful for once," Reding said.

It turned out that the plumber who worked on Peters' house was actually named Gustaf Otto Johnson, who was born in Sweden in 1872, immigrated to the U.S. in 1890 and married Nellis O. Ekblad in 1915.

According to a 1915 journal of plumbing, heating and ventilation called "Domestic Engineering," G. Otto Johnson, "a well-known plumber of Minneapolis" and his new bride honeymooned on a trip to Milwaukee, Muskegon, Grand Rapids and Chicago.

Returning to its rightful owners

Otto and Nellis had four daughters, and thanks to the online researchers, Peters was able to get in contact with Johnson's granddaughter.

Lynda Bornhoeft, of Big Lake, Minn., said her grandfather died in 1946, before she was born. But she was "blown away" to get a call from Peters saying he had a toilet that her grandfather had signed nearly 100 years ago.

"I was kind of surprised," she said.

Peters wanted to make sure the piece went with Johnson's family before the house was listed. The two arranged to meet at the home and Peters presented the toilet tank lid to Bornhoeft in late February. Johnson's granddaughter said she might hang the family heirloom in her laundry room.

But one thing is for sure: Bornhoeft is grateful to have it as a keepsake. And she's just as grateful that a collective of online sleuths got involved to make it happen.

"It's something of my grandpa," she said.