The San Francisco Public Utilities Commission received reports of a ruptured water main at Mission and Randall streets at 5:43 a.m., commission spokesman Tyrone Jue said.
Don Nugent, a manager at Don’s Auto Service, said that as of about 8:30 a.m., water was running down the street, but that it looked like crews had almost finished stopping the leak.
He said repair crews blocked at least one lane on Mission Street while they worked.
Repairs to the 2-inch main were still under way as of 11 a.m.
Water service in the area was not affected by the break.