SF rent increase cap (for unit < 1979) is 60% of regional CPI.
CA rent increase cap (for unit < 1995) is either 5% plus the increase in the regional CPI, or 10% of the lowest rent charged at any time during the 12 months prior to the increase-whichever is less.
My understanding is that units built after 1995 has no rent increase limit. someone please confirm this.
Like chent12 said, devils are in the details.