On Monday, July 30, 2012, Long Island letter carrier Mario Serrano was delivering mail when he noticed something wrong. Serrano was in front of a house along his route occupied by a single eighty-seven-year-old woman whom he checked in on six days a week. He discovered mail in the box from Saturday and, according to him, “that’s a red flag.” He heard running water, and when he rang the doorbell he heard screams for help. Serrano opened the window, entered the house, and found her stuck between her bathtub and her toilet, where she had fallen on Saturday and remained unable to get up for two days. Serrano called the police and waited with her until they arrived.

In the past few years, stories abound of letter carriers who save lives. There was the Cleveland letter carrier who saved a ninety-one-year-old man’s life after noticing piled-up mail and no footprints in the snow; a Houston letter carrier who saved two children from a burning home; an Akron letter carrier who saved a woman who was trapped for six days in her bedroom after an ulcer erupted; a Rye Brook letter carrier who rescued an elderly couple from a burning home; an Idaho mailman who saved a church after the gas had been left on for over twelve hours; and many others.

These stories of letter carriers checking in on elderly or sick residents, or helping people whose lives are in danger, occur every day across the country. In part, this is the result of the Carrier Alert program, which has been run jointly by the Postal Service and the National Association of Letter Carriers (NALC) for more than three decades. To sign up, all you need to do is notify your letter carrier, and he or she will make a special point of checking in on you and your property. The program’s literature describes the signs of trouble that letter carriers keep an eye out for, such as “lights burning in midday, pet dogs crying, drawn draperies, or no tracks in the snow.”

In a sense, we are all enrolled in the national carrier program, because letter carriers often act if they see something abnormal. In fact, the Postal Service encourages it and considers it part of the services they offer, says Phil Dine, a spokesman for NALC.

Historically, it is not uncommon for the Postal Service to perform services of public good. Pam Donato, community and membership outreach coordinator for NALC, explains that prior to instituting the current program letter carriers used to do social service checks in rural communities, acting as providers of low-level health care. For example, mailmen would weigh children for parents concerned that their children were not well nourished, and sometimes even transport infants and toddlers in their mail sacks upon request.

According to mailman Michael Plaskon, who also serves as the vice president of NALC in Pittsburgh, letter carriers these days remain attuned to the habits of residents, and notice when something is off. “When carriers get a route, they become part of a community; they are the eyes and ears of that community. We’re in the same place at the same time six days a week. We realize when something’s not right. It’s part of our duty to help.” Charlie Rose, a mailman in Athens, Ohio, who has detected and reported sixteen gas leaks while on his route, echoed this sentiment, explaining, “We’re not only letter carriers. We’re also like a safety net of service.”

In 2011, the last year for which figures are publicly available, the Postal Service recognized 331 “national employee heroes.” These are individuals who “risk their own safety to save the lives of the customers they serve.” According to Plaskon, the real number of letter carriers that save people’s lives while on their route is much higher than the recognized “national heroes.” “A lot of people don’t want publicity. I’ve known carriers who save residents without telling others. We don’t do it for the publicity; we do it because we’re concerned.” Donato explains that these stories are the ones where residents have taken it upon themselves to write a letter to the manager of their local post office or contact the local news.

Now, as the Postal Service has proposed discontinuing Saturday mail delivery in order to save $2 billion annually, these ancillary services will suffer. Straightforwardly, a 17 percent reduction in the number of visits letter carriers make could lead to a 17 percent reduction in the number of lives they save, or about fifty-five deaths a year. And the increased mortality could well be greater. As Plaskon explains, the program will become far less efficient as the number of delivery days is reduced and the gaps between service are increased. An elderly lady who falls in the bathtub could have to wait from Friday to Monday before being discovered.

Though it may seem impossible to assess the value on the number of lives saved annually by letter carriers, it is not, in fact, hard to do. Federal agencies routinely use what’s known as the “value per statistical life,” or VSL, to calculate the costs and benefits of saving a life in a variety of circumstances. Currently, agencies place the value of a statistical life in a range between $6 million and $12 million, meaning that a conservative estimate of the value of the lives saved by the Postal Service on Saturdays alone is approximately half a billion dollars annually. If the number of individuals saved is much higher, as suggested by some, then that number may run into the billions.

For Pam Donato, it’s more than a numbers game. Because most people are off work and school on Saturday, she says, it’s the day when letter carriers are most likely to see and talk with the residents on their route. “I fear that not being there on Saturday will distance the family and household from us—they won’t see us,” Donato said. “If they don’t see us, and we don’t see them, we have lost the magical connection of one human being in the air space of another.”

Beyond situations where lives are saved, letter carriers also provide human contact to many who receive no other human contact. As America is increasingly becoming an older society, the connections that letter carriers provide will become even more important. Michael Plaskon told of how, when he first started as a letter carrier, he always had biscuits for dogs, and lollipops and rubber bands for kids. (“I quickly learned not to give out rubber bands to the kids because they shoot you with them,” he said.) Plaskon also befriended a ninety-year-old woman on his route, and soon began to time his lunch hour so he could eat with her. “She lived alone, and I was the bright spot of her day,” he said. “When I had a child, I took my newborn baby to see her on my day off.”

Rick Onder, a letter carrier in Pittsburgh, described an elderly woman on his route whom he has helped multiple times after she’s fallen and not been able to get back up. One time she called him at work in the early morning to ask for help, and he got in his truck and acted as a first responder. In the media these acts are often interpreted as acts of a good Samaritan who happens to be a letter carrier. But officials and letter carriers emphasize that the Postal Service encourages letter carriers to go beyond in helping residents, creating a culture where letter carriers see these deeds as part of their duty.

In an increasingly technological world, the Postal Service upholds one of the more profound promises of this age: for forty-six cents, an actual human being will deliver a real, physical thing to anywhere in the United States, even in expanses and vistas that broadband cannot yet reach. And, as a free service, this person will keep an eye on your home, provide human contact to an ailing parent, and act if something seems wrong. The Postal Service isn’t any more obsolete than the U.S. Constitution, which enshrines it as a foundational institution of American life—including, let us hope, on Saturdays.

Moshe Z. Marvit and Jason Bacasa

Moshe Z. Marvit and Jason Bacasa . Mr. Marvit is a fellow with the Century Foundation and the coauthor (with Richard Kahlenberg) of the book Why Labor Organizing Should Be a Civil Right. Mr. Bacasa is a freelance writer and creative director for Unionosity.