Twelve years ago, a reservoir called Folsom Lake, about 30 miles northeast of Sacramento, dried up. On the drought-cracked bottom lay a clay pipe, submerged since 1955, when the reservoir was built. That pipe, like most that run below cities like Sacramento, San Francisco, and Los Angeles, was made by Gladding, McBean, a terra-cotta manufacturer that’s been around almost since California joined the Union.

After reading an ad for a clay deposit in 1875, Charles Gladding left his job making sewer pipes in Chicago and set out for the Sierra Nevada foothill town of Lincoln. Together with partners Peter McGill McBean and George Chambers, he built a factory and began making terra-cotta sewer pipes and, with the aid of the expert artisans who immigrated to California, quickly expanded into terra-cotta roof and floor tiles, and, during the Depression, garden pots and houseware.

The factory still sits prominently at the end of Lincoln’s main road. Its role in putting the town on the map is palpable in street names, architecture, and the workforce it employs. It’s full of archaic beehive kilns and pallets of pipe pieces drying in the warm, arid air. There’s a quiet hum of movement as workers cart clay around and operate the kilns. While this work looks much like it did in the 19th century, Gladding, McBean workers are applying cutting-edge technology to the traditional process.

Jamie Farnham, who runs the architectural terra-cotta department, takes me to the drafting room, where they are working on restoring the nose of New York’s iconic Flatiron Building. They use laser scans to create a digital blueprint that will be crafted with a CNC machine and then hand-detailed in the studio a floor below. Fragments of the ornamental designs, swirls, gods, and gargoyles, are spread over the floor. “Back in the day, there were over 200 terra-cotta manufacturers. Now there are only two,” Farnham said. As cement block and steel construction replaced terra-cotta, Gladding shifted to restoration. Today, a curving endpiece of The Ansonia, a Beaux Arts–style apartment hotel in Manhattan dating from 1905, awaits inspection.

Clay pipes make up the other half of Gladding’s business. Municipalities specify terra-cotta because it outlasts other kinds of pipes and doesn’t produce microparticles like PVC pipes. “What excites me most about what we do here is that it’s all natural,” said Ejidio Modolo, the plant’s operations manager. “We take clay, form and cook it, and then put it back in the ground. From the pipes to the smallest things we make, it’s all recyclable.”

“When I first walked in here, I really fell in love with it,” Farnham recalled. Like most of her colleagues, she’s worked at the plant for decades.

Gladding was in danger of closing in 1976 when Pacific Coast Building Products, which makes just about everything that goes into constructing a building, rescued it. Pacific Coast is a third-generation, family-owned company, and its culture fit well. But Gladding, McBean also benefited from the preservation laws passed in cities like New York, Chicago, and San Francisco. The preservation movement means that old buildings built in the terra-cotta heyday will continue to need alternations in period style and materials.

In a yard outside, wildflowers grow up through the concrete. This is where workers lay out tiles to view the array of glazes, mixed by a chemical engineer, in natural light. Atop a building that once housed the factory nurse and vet are an array of Spanish roof tiles they fire in a kiln the length of a football field. A computer monitors the firing process now; in the past, people lifted up the bricks to check. Instead of painting the tiles, Gladding is unique in using a technique called flashing—exposing the baking tiles to different levels of oxygen—to produce their colors. (Stanford University’s campus uses Gladding tiles, and has its own mix, Farnham told me.)

“The strength of terra-cotta comes from its plasticity,” said Modolo. It’s an ancient material with the durability to serve us long into the future. That Gladding, McBean is thriving speaks to its enduring value.

Elizabeth Snowden is a writer based in the Bay Area, where she also directs PALLAS.

Christopher Payne specializes in architectural and industrial photography. Trained as an architect, he is fascinated by design, assembly, and the built form. He is the author of several books, including Asylum: Inside the Closed World of State Mental Hospitals (The MIT Press), and most recently, Made In America (Abrams). He is represented by Esto.