At its peak, the break was spewing 9,600 gallons of water per minute, said Michelle Vargas, spokeswoman for the Los Angeles Department of Water and Power.
The break near Sunset Boulevard and North Olive Drive occurred at 2:18 p.m., and authorities are still trying determine the extent of damage. Live aerial television news footage showed water overflowing storm drains along the Sunset Strip near the Comedy Store and House of Blues, and vehicles driving through pools of water.
The steel main belongs to the LADWP.
As of 5:20 p.m., there were no reports of customers without water due to the break, but that may change as officials shut down the pipe for repairs, according to the LADWP.
The shutdown process is complicated as it involves approximately 15 valves that have to be hand-turned in a coordinated manner to isolate the pipe, according to the LADWP.