Could severe water shortages short-circuit the US shale gas boom? With 64% of the country in drought, water is looming as the next hot-button issue in the debate over hydrofracturing, also known as fracking, which involves injecting chemical-laden water under high pressure to create fissures in subterranean rock formations so gas and oil can be extracted.

A comprehensive survey of fracking and water availability, due to be released Thursday, found that 47% of oil and gas wells are located in high or extremely high water-stressed areas. The report compiled by Ceres, the Boston-based nonprofit that promotes corporate sustainability, is based on water consumption information from 25,450 wells reported by drillers to a database called FracFocus between January 2011 and September 2012.

When Ceres researchers drilled down into the data by correlating the water consumption data with water stress maps created by the World Resources Institute, they found widespread water shortages in some of the US’s most gas-rich states.

In Colorado, 92% of 3,862 wells were in areas designated as extremely high water stressed, meaning that 80% of the available water is already being drawn down for residential consumption or for industrial and agriculture use.

In Texas, which is suffering through a long-running drought that has devastated cattle ranchers and farmers, 51% of wells are in high or extremely high water-stressed locations. Tarrant County, Texas, alone consumed 10% of all water used in fracking in the state, according to the report.

“Prolonged drought conditions in many part of Texas and Colorado last summer created increased competition and conflict between farmers, communities and energy developers, which is only likely to continue,” the study found. “In areas such as Colorado and North Dakota, industry has been able to secure water supplies by paying a higher premium for water from other users or by getting temporary permits. Neither of these practices can be guaranteed to work in the future.”

During the study period, drillers nationwide used 68.5 billion gallons of water—equivalent to the amount 2.5 million people would consume in a year. But Ceres researchers said that number most likely underestimates water use by fracking because disclosures to the FracFocus database are voluntary.

So what is to be done?

Report author Monika Freyman, manager of the Ceres water program, tells Quartz that some drillers are using recycled water and tapping non-drinking water sources such as wastewater and saltwater. Recycling rates for fracking water have hit 40% in Pennsylvania, for example.

While much of the controversy over fracking has centered on water pollution, Freyman said investors should start paying attention to a more basic issue: Fracking is an incredibly water-intensive process, and there isn’t that much to go around.

“I think the focus is starting to look more at the water sourcing issues, especially in Texas and Colorado as the drought continues,” she says. “We’re really asking for far more disclosure from operators, and from an investor perspective we want to see far more quantifiable numbers of water use by region.”