MIDLAND — When the rain stopped falling in Texas, the prairie grass yellowed, the soil cracked and oil drillers were confronted by a crisis. After years of easy access to cheap, plentiful water, the land they prized for its vast petroleum wealth was drying up.At first, the drought that took hold a few years ago seemed to threaten the economic boom that arose from hydraulic fracturing, a drilling method that uses huge amounts of high-pressure, chemical-laced water to free oil and natural gas trapped in deep underground rocks. But drillers have found a way to get by with much less water: They recycle it using systems that not long ago they might have eyed with suspicion. “This was a dramatic change to the practices that the industry used for many, many years,” said Paul Schlosberg, co-founder and chief financial officer of Water Rescue Services, the company that runs recycling services for Fasken Oil and Ranch in West Texas, which is now 90 percent toward its goal of not using any fresh water for fracking.Before the drought, “water was prevalent, it was cheap and it was taken for granted,” he added. A few years ago, many drillers suspected that water recyclers were trying to sell an unproven idea designed to drain money from multimillion-dollar businesses. Now the system is helping drillers use less fresh water and dispose of less wastewater. Recycling is rapidly becoming a popular and economic solution for a burgeoning industry. The change is happening so swiftly that regulators are racing to keep up and in some cases taking steps to make it easier for drillers to recycle. Fracking operations require millions of gallons of relatively clean water. Each time a well is drilled, about 20 percent of the water eventually re-emerges, but it is packed with contaminants from drilling chemicals and heavy metals picked up when the water hits oil. Until recently, that water was dumped as waste, often into deep injection wells.Many companies, each using slightly different technology and methods, are offering ways of reusing that water. Some, like Schlosberg’s Water Rescue Services, statically charge the water so that waste particles separate and fall to the bottom. Those solids are taken to a landfill, leaving more than 95 percent of the water clean enough to be reused for fracking. Other operators, such as Walton, Ky.-based Pure Stream, offer two technologies: one that cleans water so it can be reused in the oil patch, and a more expensive system that renders water clean enough to be dumped into rivers and lakes or used in agriculture. Todd Ennenga, Pure Stream’s vice president of business development, said interest in the technology has doubled in the past year.In Texas, the fracking boom began around 2009, just as the state fell into years of drought. Especially hard-hit were South and West Texas, where rock formations have proved to be rich sources of oil and gas. Residents who were told to cut back on lawn watering and car washing grumbled about drillers hogging water supplies. In Texas, requests for recycling permits rose from fewer than two a year in 2011 to 30 approved applications in fiscal 2012. So the Texas Railroad Commission, which oversees oil and gas operations, revamped the rules in March, eliminating the need for drillers to get a permit if they recycle on their own lease or on a third party’s property. Commission spokeswoman Ramona Nye said in an email that the new rules are designed to “help operators enhance their water conservation efforts” and encourage recycling.