Back in 2009, a 64-inch pipe, one of the largest in L.A., burst in Studio City, flooding surrounding homes and businesses.
An expert on infrastructure now tells CBS2's Kristine Lazar that when it comes to the city's underground water system, things are only expected to get worse.
"Los Angeles has around 20 percent of the network more than a 100 years old. So those pipes, they have a life cycle of 100 years. So 20 percent of the network is vulnerable," said Lucio Soibelman, a professor at USC's School of Engineering.
Soibelman says the only way to truly prevent disasters like Tuesday's break is to investigate all trunk lines. It's something he says the L.A. Department of Water and Power doesn't do - and probably never will due to liability concerns.
"If you inspect those pipes and you know that they are in critical condition, we are very liable if we don't replace them. When we don't inspect them and breaks happen, it's an act of God," he said.
Soibelman estimates the cost of fixing the nation's aging underground pipes could tally in at $1 trillion.
The LADWP operates roughly 500 miles of trunk lines in the L.A.-area. The city has identified some of the lines most in need of repair.
Six improvements projects are underway, mostly in the San Fernando Valley.
Josh Zuker, meanwhile, says he empathizes with those affected by the damage in Westwood, because he won't soon forget when a trunk line burst next to his own home in Coldwater Canyon five years ago, the last time a trunk line burst before Tuesday's incident in Westwood.
"[We] opened up our front door right here and the water was literally ... it was like a lake," Zuker said.
"Every time one happens, it brings [those memories] back. No matter where they are in the Southland here, it brings back memories. Like, 'I know what is going on there.' "
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