The looming danger of a water-depleted America is unacceptable for University of Arizona law professor Robert Glennon, a nationally-recognized water expert who spoke last Tuesday at the Franke Institute for the Humanities.

“We think, in the United States, of water as infinite and inexhaustible. But in fact, for very practical purposes, it is very finite and very exhaustible," said Glennon, author of

Unquenchable. "I have a simple-minded notion of our water supply as a giant milkshake glass. What many states in the U.S. do is permit a limitless number of straws in the glass. It is the epitome of the tragedy of the commons."

Glennon pointed to Las Vegas as the “very epitome of wretched excess." The Bellagio water fountain on the Las Vegas Strip uses millions of gallons of water per year, while the city pays residents to rip out their lawns to cut down on water consumption. “It is true that we are drinking the water that the dinosaurs drank but we are using it in ways that are unsustainable. It took thousands of years for this water to accumulate and yet we are using it up in mere decades,” he said.

All over the country, water shortages have forced state governments to find any forms of viable, reusable water sources. “In nearby Lake Superior, [the water level is] too low to float two fully loaded cargo ships, requiring offloading of hundreds of tons of freight and dramatically increasing the price of shipping," Glennon said. “It’s not the usual recitation of environmental harm. This is about the health of the American economy."

Given the potential water crisis, there is no silver bullet solution, Glennon said. “We have instead a portfolio of options. There is no single template for every community.”

Glennon advocated for keeping water distribution local and enforcing aggressive conservation of water sources. He also defended "toilet to tap" water treatment plans.

“People don’t want to think about drinking sewage [but] there are plenty of things we can do with reclaimed water other than drinking it.”