The Los Angeles metro area, home to more than 18 million people, could be one major earthquake along the famed San Andreas fault away from losing most of its water supply and causing a $50 billion economic disaster.

That's because Los Angeles gets 88 percent of its water from the Colorado River, Owens River Valley and the Sacramento and San Joaquin River Delta, all hundreds of miles away, transported to the area via three aqueducts (Colorado River Aqueduct, Los AngelesAqueduct and California Aqueduct) that, combined, cross the San Andreas Fault 32 times, reports the Los Angeles Times.

A study conducted by the Los Angeles Mayor's office found that a magnitude-7.8 earthquake along the San Andreas fault could disrupt the city's water supply for 15 months, causing a massive water shortage that could last six months, causing $50 billion in economic losses alone.

"The water system is the utility most vulnerable to earthquake damage, and that damage could be the largest cause of economic disruption following an earthquake," the mayor's report reads in part.

"Portions of the system are more than a century old and vulnerable to many types of damage. Lack of water would impede recovery and the long-term loss of a water supply could lead to business failure and even mass evacuation."

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Indeed the city says it took nine years for Los Angeles' water systemto recover completely from the magnitude-6.7 NorthridgeEarthquake (seen in the slideshow above), centered just to the northwest of Los Angeles in 1994, and that quake wasn't along the San Andreas fault.

In the event of a major earthquake along the San Andreas, the Colorado River Aqueduct's flow could get cut off after the quake lifts the structure up to 13 feet in some places, the Los Angeles Aqueduct could collapse and block its flow and the California Aqueduct could be pulled apart and hemorrhage water, Craig Davis of the Los Angeles Department of Water and Power (LADWP) said.

As a result, Los AngelesMayor Eric Garcetti is trying to prioritize protecting and backing up the three aqueducts as a part of his larger plan, dubbed "Resilienceby Design," to protect the city's infrastructure from the "Big One."

Resilience by Design outlines a number of recommendations for preventing the worst possible scenario should an earthquake strike, including increasing local backup water sources, retrofitting local piping with "seismic resilient" pipes to prevent damage to aging infrastructure and proposing a"Seismic Resilience Water Supply Task Force" involving the various agencies in charge of the aqueducts to come up with a plan to protect aqueducts from damage.

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Garcetti has asked for initial plans from Los Angeles officials by July 2015, but the LADWP already has already started drawing up some, including an idea to run a plastic pipe through the Los Angeles Aqueduct in an attempt to prevent the aqueduct from blocking off completely in a quake.

What ideas come to fruition remains to be seen, but Garcetti appears committed to providing money and resources to accomplish a modern makeover of the city's infrastructure.

"This [plan] is not intended to simply be the latest 'blue ribbon commission' report that sits on a shelf," Garcetti said. "It’s designed so that government, property owners, and commercial and residential tenants can come together to strengthen Los Angeles against a known and major threat to life, property, and our economy."

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The Green Bridge passes over full water levels at a section of Lake Oroville near the Bidwell Marina on July 20, 2011, in Oroville, California. (Paul Hames/California Department of Water Resources/Getty Images)