Fracking is a thirsty technique — and most of the fracking underway in the U.S. is occurring in regions suffering from drought.

That’s according to a new analysis by Ceres, which reveals that frackers used 97 billion gallons of water to stimulate nearly 40,000 wells from January 2011 to March 2013.

Here’s a chart from the new report, showing that Anadarko Petroleum is the worst offender when it comes to tapping parched regions for water used in fracking operations:

Click to embiggen.
Ceres
Click to embiggen.

The water-hogging practices of fracking companies are a major worry in water-stressed parts of the American West like Colorado and Texas. Californian environmentalists have been calling on Gov. Jerry Brown (D) to order a suspension of fracking to protect water supplies during the state’s record-breaking drought.

Here are some highlights from the Ceres report:

Nearly half of the wells hydraulically fractured since 2011 were in regions with high or extremely high water stress, and over 55 percent were in areas experiencing drought. …

In Colorado and California, 97 and 96 percent of the wells, respectively, were in regions with high or extremely high water stress. In New Mexico, Utah and Wyoming, the majority of wells were in high or extremely high water stress regions. In Texas, which currently has the highest concentration of hydraulic fracturing activity in the U.S., more than half of the wells examined (52 percent) were in high or extremely high water stress regions. …

Shale development in many regions is highly reliant on groundwater resources, which are generally less regulated than surface waters, thus increasing risks of water resource depletion and water competition. Over 36 percent of the 39,294 hydraulically fractured wells in our study overlay regions experiencing groundwater depletion.

Here’s a list of counties that are feeling the worst of it:

Click to embiggen.
Ceres
Click to embiggen.