Residents described fast-moving water and significant damage in the aftermath of the break.
"The water was like a rapid," Angelo Burlos said.
Tom Demille said the flooding left mud inside his apartment complex.
"There's about three inches of mud downstairs where I live," Demille said.
For many homeowners and renters dealing with water damage inside their homes or apartments, insurance coverage may be limited, according to Rick Dinger of Crescenta Valley Insurance.
"As far as insurance goes, unfortunately, they're out of luck," Dinger said.
Dinger said the issue stems from the relatively small number of California homeowners who carry flood insurance, estimating that only about 1% do.
"You see the fires and then you've got a little bit of relief knowing that most people have fire insurance," Dinger said. "But when there's a flood, you know only 1% have flood insurance, 10% have earthquake insurance -- so even earthquakes are better than floods when it comes to disaster."
He said the situation differs from a pipe bursting on a homeowner's own property, which would likely be covered by standard insurance policies. But in a large-scale flooding event such as the West Hollywood pipe break, he said flood insurance would generally be required.
Dinger also said renter's insurance does not cover this type of damage.
"Basically, your only option is subrogation, going after if it was some negligence or something that the city did and trying to go that direction," Dinger said.
The outlook is better for vehicle owners whose cars were damaged by the flooding, Dinger said.
"As long as they've got comprehensive coverage, which is an act of God considered, that would be covered. So they pay their deductible and the insurance carrier picks up the balance," he said.
Dinger said the incident may prompt more Southern Californians to consider flood insurance, particularly as infrastructure across the region continues to age.
"It should be a pretty good notice to people that this could happen and you want to have some insurance coverage," Dinger said.