The southbound side of Laurel Canyon Boulevard between Mulholland Drive and Ventura Boulevard opened again by 12:30 p.m. after the rupture happened, which was reported at about 6 a.m. One lane in each direction was opened.
The northbound lanes, from Hollywood into Studio City, were back open shortly before 11 a.m.
Los Angeles Department of Water and Power crews were working to repair the main and advised drivers to find alternate routes in the meantime.
The road buckled up and sent a rushing river of water down the hill. It was powerful enough that Annie Little lost her mail box.
"I'm assuming the water took it swiftly down the road," she said.
Crews were able to stop the flow of water just after 9 a.m. It was then that the city decided to shut down Laurel Canyon Boulevard to break open the road and make necessary repairs.
LADWP said it hopes to have the repairs to the water main done by Thursday night, and wants to have the road repaired for the Friday morning commute. It still urges drivers to avoid the road for the rest of Thursday.
The exact cause of the water main break is still under investigation.