Last year, the Federal Bureau of Land Management tried to unload 1,947 acres of land on the outskirts of Henderson, Nev., just outside Las Vegas. It received no bids because of a high price tag (about $250 million) and constraints on how the property could be developed. This year, it changed a few parameters and again offered the land to the highest bidder and made the sale to a consortium of eight builders for a cool $557 million. The money is supposed to go toward protecting at-risk environmental assets in the region.

But considering the dire situation surrounding the Las Vegas water supply, a land deal of this magnitude is a risky proposition. Lake Mead, the source of most of the area's water, has dropped to historic lows because of a prolonged drought and spiraling demand. The city has issued several drought restrictions after draining its own aquifers to the point that buildings have begun sinking with their foundations. The Southern Nevada Water Authority is trying to build a pipeline to extract water from three nearby lakes to fuel the ever-increasing demand for water in the Las Vegas region.

Builders in the region already control thousands of additional acres and intend to develop them in coming years. With a thousand new residents arriving in Vegas each week, what happens when the well runs dry?

Learn more about markets featured in this article: Las Vegas, NV.