Propositions 60 and 90

In most cases, these constitutional tax initiatives allow senior citizens to transfer the trended base value from their current home to a replacement property if certain requirements are met. This may result in substantial tax savings.

Who Qualifies?
If you or your spouse that resides with you are age 55 or older, you may buy or construct a new home of equal or lesser value than your existing home and transfer the trended base value to your new property.

This is a one-time only benefit. You must buy or complete construction of your replacement home within two years of the sale of the original property. Both the original home and the new home must be your principal place of residence. A claim must be filed within three years of purchasing or completing new construction of the replacement property. If a claim is filed after the three-year period, relief will be granted beginning with the calendar year in which the claim was filed.

Proposition 60 allows for the transfers of a base year value within the same county (intracounty). Proposition 90 allows for the transfers of a base year value from one county to another county in California (intercounty) if the county has authorized such a transfer by an ordinance.

Source: https://assessor.lacounty.gov/propositions-60-and-90/

Source: https://www.boe.ca.gov/proptaxes/prop60-90_55over.htm