East Coast firms have bought up thousands of acres of irrigated land across the Southwest, local officials told CNN. Water Asset Management, a New York-based investment firm, has become one of the biggest players in the field, with purchases in Arizona, California, Colorado and Nevada as well as pending deals in New Mexico and Texas.

Water Asset Management president Matt Diserio has called water in the United States “a trillion-dollar market opportunity,” and said he started the company “on the core belief that scarce clean water is the resource defining this century, much like plentiful, cheap dirty oil defined the last century.”