A fracking site in Colorado. Between January 2011 and May 2013, 97 billion gallons of water were used for fracking. Ed Andrieski/AP

As states from Arkansas to California deal with economically crippling, record-breaking droughts, a new report has found that hydraulic fracturing — a process of drilling for oil and natural gas also known as fracking — could further deplete scarce water resources.

The report, issued by sustainable investing consultancy Ceres on Wednesday, found that since 2011 nearly half of all fracking wells were located in areas with high levels of “water stress.” Ceres defines water stress as occurring where “80 percent of available surface and groundwater is already allocated for municipal, industrial and agricultural uses.”

Fracking — a process in which thousands of gallons of water are mixed with chemicals and pumped deep into the earth to break up naturally occurring gas and oil formations — has been controversial since the practice boomed in states like Pennsylvania and North Dakota in the mid-2000s. Activists and many residents near fracking sites argue it pollutes the environment and causes health issues. Fracking companies and other proponents say it can be done safely and creates jobs for local communities.

But no one argues that fracking can be done without water. Environmentalists say they hope the new report adds another weapon to the arsenal used to dispute industry claims about fracking’s sustainability.

“Proponents of fracking tout their ability to recycle water, but once water enters the fracking process, even if it’s recycled for fracking, it’s unlikely to enter the (environment) again,” said Dani Neuharth-Keusch, an activist at Environment Texas. “As we’re in this extreme drought, this report is another valid argument to point to against fracking.”

The Ceres report was based on data for 39,294 wells listed on FracFocus.org, an industry-funded site where fracking companies disclose where they drill and, to a certain extent, what they put in their wells.

It found that between January 2011 and May 2013, 97 billion gallons of water were used for fracking.

Much of the water used was in Texas. In 2012, half of all fracking water usage occurred in the state. The Department of Agriculture recently deemed Texas a disaster area because of its drought.

Agriculture is still by far the biggest user of water in the country, including in Texas, where it accounts for over 50 percent of usage. Fracking accounts for under 1 percent of water use in the state, but that number is growing. Environmentalists point out that in areas where fracking is concentrated, that number can be much higher.

In parts of Texas sitting atop the Eagle Ford shale, one of the biggest natural gas plays in the country, fracking accounts for up to 50 percent of water usage.

While Texas is the biggest consumer of water for fracking, it’s not the only state seeing trouble as it tries to weigh the economic benefits of the procedure against its environmental costs.

The Ceres report identified 30 counties where over 1 billion gallons of water had been used for fracking. Many of those counties were in Colorado and California, which are both currently experiencing unprecedented droughts.

California declared a state of emergency because of the drought last month. The state’s reservoirs are currently less than 50 percent full, and snowpack in its mountains are at 20 percent of the average.

But the drought conditions in Western and Southern states don’t appear to be slowing down fracking permits.

Ceres points to outdated, loophole-ridden water regulations that allow unlimited amounts of water to be used for fracking. It’s unclear if there’s political will to change any of those regulations.

Texas, for example, requires permits for using surface water but not for groundwater, which is more commonly used for fracking.

It’s also uncertain if Texas, and other states experiencing an economic boom thanks to fracking, are willing to enforce existing regulations that could potentially make drilling less attractive or lucrative.

When a Parker County man accused the fracking company Range Resources of polluting his water in 2012, the state’s environmental agency refused to investigate. When the federal Environmental Protection Agency intervened, Texas politicians accused them of overstepping their bounds, and the agency dropped its investigation late last year.

That, environmentalists say, may be an omen for the future of water supplies in fracking-friendly states.

“The legislature, they don’t want to hear it,” said Wilma Subra, an environmental scientist and anti-fracking activist who has studied the health and environmental issues posed by fracking in Texas. “Meanwhile, people are having to cut back on cattle because there isn’t enough (water). Pastureland is going dry.”