I have one possible explanation. Proposition 13 limits property tax increases to 2% per year in California. As a result, many homes are taxed at far below the

I have one possible explanation. Proposition 13 limits property tax increases to 2% per year in California. As a result, many homes are taxed at far below their market value. If a lot of long term residents with dirt cheap property tax sold during that period you could see a dramatic bump in average tax per household.