The New Yorker's Ryan Lizza pointed to Colorado's Front Range as a window into the political future of the American West, but Las Vegas might be a better place to look for a glimpse at the region's environmental future—no city, after all, is closer to running out of easily available water. Las Vegas has already maxed out on its quota of 300,000 feet of water per year from the Colorado River, despite an innovative program under which it gets credit for the treated wastewater it puts back in the river. Unless Nevada calls for renegotiating the Colorado Compact—which, as John McCain discovered, is the nuclear option in Southwestern water politics—Las Vegas will have to meet further growth in water demand by pumping groundwater from desert valleys hundreds of miles north of the city. This could be an environmentally disastrous move—drying up springs, killing deep-rooted plants that live on the groundwater, and possibly causing horrific dust storms as a result. It could also be disastrously expensive: Cost estimates vary based on interest rates and other things, but all agree that the water would end up costing more than $1,000 per acre-foot.

There's a much cheaper option, though: not using as much water in the first place. According to an analysis by the Pacific Institute, installing ultra-low-flow toilets instead of the regular kind saves water at a cost of just $50 per acre-foot. Improving the efficiency of lawn sprinkler systems, by adding soil-moisture sensors that keep the sprinklers from turning on when the ground is already wet, conserves water for about $200 an acre-foot. Low-flow showerheads, meanwhile, actually have a negative cost, simply because the energy savings alone (you don't have to heat as much water) more than covers the cost of the retrofit.

The problem is that it's hard to get people to conserve water unless they have financial incentives to do so. That's why cities that are serious about water conservation have adopted steeply tiered water pricing. They keep the cost for the first few thousand gallons per month relatively low, because nobody wants to price people out of the small amount of water that's actually necessary to sustain life. But use more than that, and the price per thousand gallons rises significantly. Seattle has aggressively tiered water rates that top out at $10.50 per thousand gallons. The city uses about 100 gallons per person per day. Las Vegas, meanwhile, has rates that top out at $4 per thousand gallons, and it uses 227 gallons of water per person per day. The lesson for Las Vegas—and John McCain, for that matter—should be that it's a whole lot easier to change water prices than to start water wars. 

--Rob Inglis, High Country News