What triggers a reassessment from a change in ownership in California?

Under Proposition 13, your factored base year value stays in place until a change in ownership or new construction occurs. Cal. Rev. & Tax. Code §60 defines a change in ownership as a transfer of a present interest in real property, including the beneficial use thereof, the value of which is substantially equal to the value of the fee interest. When that happens, the assessor sets a new base year value at the property's current market value as of the transfer date — usually the purchase price.

Cal. Rev. & Tax. Code §61 lists transfers that do count as a change in ownership, and §62 lists key exclusions that do not trigger reassessment, including:

• transfers between spouses or registered domestic partners;
• transfers that only change the method of holding title without changing proportional interests;
• certain transfers into and out of revocable trusts — note §61(h) provides a change in ownership occurs when a revocable trust becomes irrevocable and interests vest in someone other than the trustor or the trustor's spouse/partner.

Why this matters for an appeal:

• A wrongly-triggered reassessment is appealable. If the assessor reappraised based on a transfer you believe was excluded (e.g., a spousal transfer or a title-method change), you can dispute that a change in ownership occurred — often via a supplemental (§75.31) or escape (§1605) assessment appeal.
• File the change-in-ownership statement on time. Doing so preserves favorable burden-of-proof treatment if value is later contested.

Proposition 19 separately narrowed the parent-child/grandparent-grandchild exclusion (see the state BOE Proposition 19 page), so inherited-property transfers now trigger reassessment far more often than before.