This story is published in partnership with the Reno Gazette-Journal, with support by The Water Desk, an independent journalism initiative based at the University of Colorado Boulder’s Center for Environmental Journalism.

For the first two decades of the 21st century, not even a once-in-a-millennium drought could deter real estate developers from building vast suburban tracts on the wild edges of Western U.S. cities. But in 2021, a reckoning appeared on the horizon. The Colorado River sank to historic lows, winter rains never arrived, and communities from California to Texas found their groundwater wells going dry after decades of overuse.

Western officials had seldom let questions about water availability get in the way of population growth, but suddenly they seemed to have no other choice. Faced with an unprecedented shortage, many local governments tried to pump the brakes on new developments. A small town in Utah halted all new housing permits, fearful that more homes would sap a local river. A suburb of Colorado Springs, Colorado, told developers that it could no longer allow new subdivisions to connect to the city’s water system. Most significantly, the state of Arizona has all but paused new housing in some Phoenix suburbs, citing a shortage of groundwater.

This pivot to conservation was bad news for D.R. Horton, the nation’s largest homebuilding company. Buoyed by pandemic-induced demand for cheap, spacious housing across the West, Horton netted $6 billion constructing more than 80,000 homes last year alone. The company had long been able to assume that if it built a development, someone else would provide water for it — usually a local government eager for tax revenue. All of a sudden, Horton had to find the water itself.

Luckily, there was a third party who could help.

In April of last year, Horton acquired Vidler Water Company, a tiny outfit whose dozen employees worked out of an unassuming faux-Mediterranean office park in Carson City, Nevada. Though Vidler’s annual revenue was less than a tenth of a percent of Horton’s, the real estate titan spent big to snap it up: The price tag on the acquisition was an eye-popping $291 million.

Vidler is an unusual company. It doesn’t actually deliver water to people, nor does it own any facilities for water treatment or desalination. Instead the company functions as a broker for water rights, finding untapped water in rural communities and marketing it to developers and corporations in fast-growing cities and suburbs. For 20 years, the company has bought up remote farmland and drilled wells in bone-dry valleys to amass an enormous private water portfolio, then made tens of millions of dollars by selling that portfolio one piece at a time.