Sabo proposes that the Southwest cuts its water use to 60 percent. To get there, it comes down to policy and investment in infrastructure for the future.

“You would never know we had a water shortage here,” says Sabo. “We don’t pay a lot for it, we don’t expect pay a lot for it and we don’t expect to have to conserve it.”

David White, co-director of ASU’s Decision Center for a Desert City (DCDC), says that Arizona water policy has done a good job of providing adequate supplies for the growth of the region up to this point. But environmental and demographic factors will likely require changes in that system. The DCDC uses research to inform environmental policy in times of uncertainty.

“We’ve been able to deliver a consistent and reliable amount of water to residents even though the amount of water that comes into our system fluctuates wildly,” says White. “That system has been effective over the past 100 years under a set of conditions and assumptions that may be changing due to climate change, extended and prolonged droughts, and increased demand as a result of population growth. It faces new challenges,” adds White.

Home to more than half of Arizona’s population, Maricopa County grew by 24 percent from 2000 to 2010, according to U.S. Census Bureau data. Additionally, “Watering the Sun Corridor,” projects the 2030 population of Phoenix and Tucson to exceed 7.8 million.

One way to reduce water use is through the addition of more sustainable infrastructure. According to Sabo, this would be most effective in areas of growth and expansion, such as Ahwatukee, Anthem and Sunrise.

“Retrofitting historical Phoenix would be a pain in the neck,” says Sabo. “The idea is to build sustainable infrastructure as we build out. Reclaimed water is cheaper to add in to unbuilt suburbs than to retrofit in older cities. When the time comes for refurbishing the old potable infrastructure in the central city, then we can consider retrofitting for dual distribution of potable water for drinking and reclaimed water for landscape irrigation at home.”

Such changes would help us follow White’s recommendation to stop siphoning our limited groundwater sources and live off of renewable surface water instead. Groundwater is water that is stored in underground aquifers. Although it is replenished by rainfall, we use it much faster than it can be replaced.

“Groundwater supplies a bank or a backup of water,” says White. “But by and large it’s a nonrenewable source and we should try to live within our means.”

It’s unlikely that the Southwest would run out of water. But as temperatures rise and population swells, how we value our water supply is going to change.

“You’re either going to have to pay more for it or you’re going to have to pay more for your winter salad,” says Sabo. “Either the farms or the luxury to use water the way we do in cities is going to go.”

Pete Zrioka, Office of Knowledge Enterprise Development, Arizona State University