Three California propositions allow you, in limited circumstances, to transfer your property tax base between properties. It is the tax base in California that is the most important factor in determining actual taxes--worth its weight in gold if you remain in a property long enough.
A tax-payer revolt in California in the late 1970s ended with the passage of Proposition 13--legislation that more or less freezes property taxes for owners based on the sales price of their homes. Under Prop 13, all properties are taxed at 100 percent of their assessed value at the time of purchase. After that, the assessed value can only be raised by the lesser of the rate of inflation or two percent. The longer you own the property, the more you benefit because while property appreciates in value, your taxes stay relatively stable.
One effect of Proposition 13 was that elder home owners on fixed incomes felt trapped in their homes after 10 or 20 years of occupancy. They might have enough equity in their homes to sell and buy smaller retirement homes or move to be closer to children, but the prospect of having to pay property taxes four and five times as much as the taxes they paid on the home they had lived in for so any years prevented them from moving. Proposition 60, passed in 1986, allows homeowners at least 55 year old to transfer their existing property tax base to a new home within the same county purchased for a price equal to or less than the sales price of the home they are vacating. The law only allows you to move your tax basis once.
Proposition 90, passed in 1988, allows counties the option of allowing seniors who move from other counties to bring their tax base with them so long as they meet the Proposition requirements of being at least 55 years old and buying a home that is equal to or less than the price of the home they have sold. As of 2011, eight counties have signed on to this arrangement: Alameda, El Dorado, Los Angeles, Orange, Santa Clara, San Diego, San Mateo and Ventura.
Proposition 110 extends the rights of Proposition 60 and 90 to the severely and permanently disabled. It also allows a property owner who becomes disabled after having used the tax-base transfer once the right to use it a second time.