Supervisor Carmen Chu, whose 4th district includes most of the Sunset District, led Ron Dudum and Dave Ferguson with about 50.2 percent of the vote, according to preliminary election results, a fraction above the 50 percent needed to avoid the ranked-choice recount system.
San Francisco's ranked-choice system, introduced in 2002, allows voters to select their top three choices for supervisor in their district.
If a candidate receives more than 50 percent of the first choices, that candidate is declared the winner. If not, candidates with the fewest first-choice votes are progressively eliminated and votes are recounted until there is one remaining candidate with a greater than 50-percent majority.
San Francisco elections officials have said that preliminary results for some supervisor races will likely be announced Friday, while the processing of mail-in and provisional ballots is expected to take up to three weeks.
In District 5, incumbent Supervisor Ross Mirkarimi garnered 77.5 percent of the vote against challengers Owen O'Donnell and Rob Anderson. District 5 includes the Haight Ashbury, Panhandle and Western Addition neighborhoods.
District 7 Supervisor Sean Elsbernd defeated Julian Lagos and Billy Bob Whitmer with 69.8 percent of the vote. District 7 includes the Park Merced and Twin Peaks neighborhoods.
In District 1, being vacated by Supervisor Jake McGoldrick, Eric Mar leads at 42.4 percent, followed by Sue Lee at 32.9 percent, and Alicia Wang at 14 percent. District 1 includes most of the Richmond District.
The District 3 race to succeed Supervisor Aaron Peskin early this morning stood at David Chiu with 39 percent, Joseph Alioto, Jr. at 23.4 percent and Denise McCarthy at 12.7 percent. The district includes Chinatown, Nob Hill, Russian Hill, Telegraph Hill and the northern Embarcadero waterfront area.
In District 9, where seven candidates were competing to succeed Supervisor Tom Ammiano, who was elected to state Assembly, preliminary results showed police commissioner David Campos leading with 35.5 percent, followed by Mark Sanchez at 29.5 percent and Eric Quezada at 21.3 percent. The district includes the Mission, Bernal Heights and part of the Portola District.
The race in District 11 to fill the seat being vacated by termed-out Supervisor Gerardo Sandoval was being led by John Avalos at 30.1 percent, followed by Ahsha Safai at 24.5 percent and Myrna Lim at 16.5 percent. The district includes the Ingleside, Excelsior, Ocean View and Merced Heights neighborhoods.