Environment Planet Earth The Mystery and Danger of Jacob's Well By John Donovan John Donovan Writer Arizona State University John Donovan is a freelance writer based in Atlanta. He writes on a range of topics including nature, health, history, and pop culture. Learn about our editorial process Updated April 18, 2022 Share Twitter Pinterest Email benedek / Getty Images Planet Earth Outdoors Weather Conservation Summers in central Texas are simply sweltering. Residents and visitors alike seek relief where they can find it—in the air conditioning, in a can of ice-cold Lone Star, or in the refreshing waters of Jacob's Well, a spring that fills a vast underwater cave to its brim. A dip into this well, however, is not for the faint at heart. Though the crystal-clear water looks inviting, it's actually rather dangerous. Discover more about this legendary well, its biblical name, and why some wouldn't dare to even dip a toe into it no matter how high the temperature rises. About Jacob's Well It's believed that settlers stumbled upon Jacob's Well around 1850. The watering hole—technically a perennial karstic spring—is 12 feet in diameter, and at the time it was found, it was spouting its thirst-inducing waters up to five feet high. The settlers didn't dive into it, of course, but treated it instead as a drinking fountain and later used it to power a saw mill. They named it Jacob's Well because of its biblical magnificence. Since the well was discovered, at least 4,500 feet of it has been explored. It's now thought to be the second-largest fully submerged cave in the state of Texas. It has an average depth of 120 feet and sits on 80 acres of protected land. The water inside Jacob's Well comes from the Trinity Aquifer, which practically spans the entire southwestern portion of the state. It no longer spouts water at 170 gallons per second due to development in the area. Today, the "fountain" has been reduced to a mere ripple on the surface. The water feeds into Cypress Creek. The cool water of Jacob's Well is a major lure in the Hill Country. Daredevils leap from a nearby outcropping into the slim opening of the well. Free-divers probe the opening, sometimes descending as much as 100 feet and maneuvering into the passageways of the underwater cave. Even scuba divers make the occasional foray into what the Jacob's Well Exploration Project calls a "challenging, unforgiving environment," though recreational scuba is not allowed. What's considered serious fun for some—lounging around on the lip of the well, escaping the heat, spending time with friends—is a lifestyle to others. A risky lifestyle, at best. The Dangers of the Well Larry D. Moore / Wikimedia Commons / CC BY-SA 4.0 The Houston Chronicle reported that a dozen people have died scuba diving in Jacob's Well, hence why it's often called one of the most dangerous diving spots in the world. In 1979, two young Texans were caught in one of the well's caves and drowned. One of their remains was flushed out of the well in 1981 while the other remained in the well until a 2000 recovery mission. The problem with diving in Jacob's Well is that its passageways become so narrow that divers must remove their tanks. Then there's the sheer depth of the cave: Diego Adame, a 21-year-old from San Antonio, lost a flipper while free diving the caves deep in the well in July 2015 and had to cut away his weight belt to make it back to the surface before his breath ran out, describing it as a death-defying experience. Even up top, though Jacob's Well can be dangerous. The well is only about 12 feet in diameter and surrounded by rock, yet many dive head-first into it. Some do flips, etc., into the upward current. Swimming is allowed, but only at-your-own-risk and between the hours of 10 a.m. and 6 p.m. Reservations must be made and last only two hours. If you choose to visit, here are some tips for staying safe at Jacob's Well: Only swim in Jacob's Well if you are a strong swimmer, and avoid diving into the well unless you have experience. Wear water shoes while swimming in the well to avoid slipping on rocks. Do not dive into the water because of the narrow opening. Follow the rules of the Hays County Parks Department, which now protects the well and manages tourism in the area. View Article Sources "One of the world's most dangerous dive sites is in Central Texas." Houston Chronicle. 2013.