numerous wastewater plants that have discharged into the river. "Most everyone lives downstream from someone," said Dorsey. "And so the water does get reused. There are so many examples of that around the country."

San Diego gets approximately 85 percent of its water from the Colorado River and Northern California, and starting this fall it is scheduled to get a new desalination plant in Carlsbad that will meet about 7 percent of the county's needs. Additionally, the city of San Diego is looking to recycle wastewater.

San Diego is targeting an initial 15 million gallon per day water purification facility to be in operation by 2023—and there's a longer-term goal of producing up to 83 million gallons of purified water by 2035, or enough to supply one-third of the city'sfuture drinking water supply. San Diego conducted a four-year demonstration project starting in 2009 and found it could produce water that met all federal and state drinking water standards.

What's more, the city also launched an outreach program to increase awareness of the toilet-to-tap water reuse and found public support rose from 26 percent in 2004 to 73 percent in 2012.

"Biggest barrier right now is the public perception piece of it," said Stanford's Choy, a former hydrologist with the U.S. Bureau of Land Management. "Eventually, once public perceptions have caught up with recycled water, that will be used for drinking water."