Proposition 60 is a law passed by the state's voters in 1986. It allows seniors to keep their property tax base assessment when they move within the same county. Proposition 60 does not require passage by a local municipality.
In 1988, the state's voters approved Proposition 90, which is designed to induce greater turnover of homes owned by senior citizens. The measure provides anyone over the age of 55 with relief from Proposition 13 by allowing them to move from one county to another without undergoing a change in their basic property taxes.
Here you can find legal FAQs and other useful information related to Prop 60 and Prop 90.