A broken valve was reported at 9:27 a.m. at a building at Kearny and Market streets.
There were reports of water coming from the top of the building, according to fire officials.
Crews responded and found the malfunctioning sprinkler system on the top level of the 12-story building, fire officials said.
No injuries were reported.
The property manager of the building at 1 Kearny St. said she could not immediately comment on the incident.
The manager at Hakkasan restaurant on the building's second floor said staff had seen the water falling, but said the flooding had not affected restaurant operations.
Tyrone Jue, spokesman for the San Francisco Public Utilities Commission, said the leak did not appear to be connected to a city-owned Fire crews left the building just before 10 a.m. A building engineer had been called to respond to the leaky valve, fire officials said.