I am asking because I am not familiar with specific map projections for the San Francisco Bay Area.
There are many coordinate reference systems (CRS) which could be used for the San Francisco area depending on what you are doing with the data. UTM zone 10 North is designed for medium scale purposes and maintains shapes and angles. San Francisco area is in State Plane California zone 3 (III). That's designed for large scale purposes. State Plane zones are also conformal which maintains shapes and angles. There's also a statewide equal area-based CRS sometimes called Teale Albers or California Albers. All of the above have multiple versions that are based on difference geographic CRS.
The City and County GIS department have also published a conformal coordinate reference system. There are two versions--one uses meters while the other uses US survey feet. In the EPSG Geodetic Registry, they are 7131 and 7132. Here's a [link](http://www.epsg-registry.org/report.htm?type=selection&entity=urn:ogc:def:crs:EPSG::7131&entity=urn:ogc:def:crs:EPSG::7132&reportDetail=long&style=urn:uuid:report-style:default-with-code&style_name=OGP Default With Code&title=sf) to a custom report with the information on the two CRS. Some of the details are below.
GeoCRS: NAD 1983 (2011) Name: NAD83(2011) / San Francisco CS13 (add "(ftUS)" for 7132) Projection: Transverse Mercator Latitude of natural origin: 37° 45' N Longitude of natural origin: 122° 27' W Scale factor at natural origin: 1.000007 False easting: 48000 m (157480 USft) False northing: 24000 m (78740 USft)
EPSG Geodetic Registry is at http://www.epsg-registry.org
Disclosure: I'm on the subcommittee that maintains the registry.