Total Property Tax in CA has been rising at a pretty good clip over the years. Barring years in recession annual collection of property taxes have increased by about 8-10%. California collects a little over $45 billion in property taxes on a total assessed value of 4.1 trillion dollars. How much bigger do you think the 4.1 trillion is in real terms.
According to the LAO http://www.lao.ca.gov/handouts/state_admin/2012/CA_Property_Tax_3_12_12.pdf
the residential real estate component is 2.2 (SFH) trillion + 770 billion (MultiFamily) ~ 3 trillion or about 75% of the total property tax collected. 2010 census data says CA has 13 million homes. The median home price in CA is about $300K so if we completely got rid of prop 13 and reassessed every house it looks like we’d potential increase the assessed value to 3.9 trillion from 3 trillion (30% more than the current assessed value). That corresponds to about 10 billion dollars in additional tax revenue. Total commercial property is about 891 billion so even if we applied a higher value like 50% to those properties we end up with about 5 billion in additional revenue.
Of course in doing so property tax revenue would become more volatile as there wouldn’t be a cushion in under assessed properties. As prices rose or fell in CA the tax revenue would do the same. Right now property tax revenue tends to always increase. A lot in the boom years and basically flat in the recession years. Without prop 13 and under-assessing property values CA’s budget might have had a 30-40 billion dollar hole when the housing market collapsed.