How does Proposition 19 affect my California property tax base year value?

Proposition 19 (effective 2021) reshaped two California property-tax transfer rules, both administered through the state BOE Proposition 19 page. The piece most relevant to homeowners is the base year value transfer, codified at Cal. Rev. & Tax. Code §69.6.

Under §69.6, a person who is over 55, severely and permanently disabled, or a victim of a wildfire or natural disaster, and who resides in a home eligible for the homeowners' or disabled veterans' exemption, may transfer the factored base year value of that home to a replacement principal residence purchased or newly constructed anywhere in California within two years of selling the original. Eligible owners may use this transfer up to three times, regardless of any earlier transfer under the old Propositions 60/90 or 110.

Why this matters for assessments and appeals:

• It can reset what your "correct" assessed value should be. If you qualified for a Prop 19 transfer but the assessor enrolled a full-market base year value on your replacement home instead of your transferred factored base year value, that is a basis to seek correction — file the transfer claim with the assessor first.
• If the replacement home costs more than the original, the difference is added to the transferred value, so the new base year value is the transferred value plus the excess.
• Proposition 19 also tightened the parent-child and grandparent-grandchild exclusion (via §63.2), narrowing inherited-property reassessment relief — a separate issue from the value transfer.

A Prop 19 dispute usually turns on eligibility and the transfer claim, handled by the assessor, rather than a standard market-value BOE-305-AH appeal. If the assessor denies the transfer or miscomputes the value, escalate through the assessment appeal and refund process.