Prop 19 and Family Property Transfers in Marin County

Two nearly identical houses can sit across the street from each other in Mill Valley and carry annual property tax bills that differ by more than $15,000. One family bought in 1994 and never moved. The other bought last year. Nothing about the houses explains the gap — only the dates on the deeds do.

That gap is what Proposition 19 governs when a Marin property moves from one generation to the next. Get the transfer right and a substantial portion of the low assessment carries forward. Get it wrong, or miss a filing deadline, and the county reassesses at full market value. In a county where family homes routinely appraise well above $1.5 million, the difference between those outcomes compounds every year the property is held.

What Prop 19 Changed

Before February 16, 2021, California's parent-child exclusion was generous and simple. A parent could transfer a primary residence to a child at any value, and the child inherited the parent's assessed value. Separately, up to $1 million of assessed value in other property — rentals, vacation homes, commercial buildings — could also transfer without reassessment.

Prop 19 eliminated the second category entirely and narrowed the first substantially. Today the exclusion applies only to a family home — one that was the parent's principal residence and that the child makes their own principal residence — and even then the protection is capped rather than unlimited. (A working family farm is the one other kind of property that still qualifies, which matters to some West Marin ranch families.) Rental properties, second homes on the coast, and investment parcels no longer qualify at all — when they pass to the next generation, they are reassessed at full market value.

The Marin math

Start with the number the whole calculation turns on: the factored base year value. That's the county's taxable value for the property under Prop 13 — what the parents paid (or what the home was worth when they acquired it), increased by no more than 2% per year since. It's the assessed value shown on the parents' property tax bill, and in a long-held Marin home it's usually a fraction of what the house would sell for today.

Under Prop 19, the child keeps that low value as long as the home's current market value is no more than the factored base year value plus a fixed allowance. The allowance started at $1 million in 2021 and is adjusted for inflation every other year; for transfers between February 16, 2025 and February 15, 2027, it is $1,044,586. If the market value is higher than the base plus the allowance, the difference is added to the child's assessed value.

Here's how that plays out on a real-world set of numbers. Suppose parents bought a house in Larkspur in 1998 for about $480,000. After nearly three decades of increases capped at 2% a year, their factored base year value is now roughly $760,000. The home would sell for $2.1 million today, and their son moves in after the transfer:

• Factored base year value plus the $1,044,586 allowance = $1,804,586
• Market value of $2,100,000 exceeds that by $295,414
• Son's new assessed value = $760,000 + $295,414 = $1,055,414

His tax bill is calculated on about $1.06 million instead of $2.1 million — roughly half of what a buyer paying market price on the same street would owe, but nowhere near the full pass-through families remember from the pre-2021 rules. (A useful shortcut: whenever the home is worth more than the base plus the allowance, the child's new assessed value simply equals market value minus the allowance.)

The Primary Residence Requirement Is Where Families Get Caught

This is the single most common failure, and it's particular to counties like Marin where the family home is often not where the adult children live.

The exclusion requires the child to occupy the property as their principal residence. Not to own it. Not to visit on weekends. To live in it, and to file for the homeowners' exemption on it within one year of the transfer.

So the family whose daughter lives in Portland and wants to keep the San Rafael house as a rental gets no exclusion — full reassessment at market value. The family whose son intends to move in eventually, but not for three years, gets no exclusion. A second home in Stinson Beach or Bolinas, no matter how long it has been in the family, gets no exclusion. The rule is about occupancy, and it's checked.

Prop 19 rewards a specific fact pattern: a family home that becomes another family member's actual home. Everything outside that pattern is reassessed at market value.

Grandparent-to-Grandchild Transfers

Prop 19 preserved a version of the grandparent-grandchild exclusion, with a condition that catches people off guard: it generally requires that the grandchild's parents — the ones who would have been the grandparents' children — are deceased as of the transfer date.

In other words, this isn't a route around the parent-child rules for a living, healthy middle generation. It exists for the situation where the middle generation is gone. The occupancy and value-cap requirements still apply on top of that, and the claim is filed on a different form than the parent-child version.

The Other Half of Prop 19

Prop 19 is usually discussed only as a restriction, but it also expanded something meaningful, and Marin homeowners are among the most likely to use it.

Homeowners aged 55 or older, people with severe disabilities, and victims of wildfire or natural disaster can now transfer their existing assessed value to a replacement primary residence anywhere in California, as long as the replacement is bought within two years of selling the original. Homeowners 55 and over and severely disabled homeowners can use this up to three times in their lives. Previously the benefit was generally usable once, was limited to the same county or a short list of participating counties, and required the replacement to cost no more than the original. Today the replacement can cost more — the difference is simply added to the transferred value.

For a couple who bought in Mill Valley in the 1980s and want to downsize to a smaller place in Novato or move closer to grandchildren in another county, this is substantial. They carry their low assessment with them rather than resetting to current market value. In practice this often makes the difference between a move being affordable and being financially irrational.

Filing Deadlines That Cost Families Money

The exclusion is not automatic. It's a claim, and claims have deadlines. In Marin these are filed with the County Assessor-Recorder at the Civic Center in San Rafael.

1. File the reassessment exclusion claim — Form BOE-19-P for parent-child transfers, BOE-19-G for grandparent-grandchild. To get the exclusion from the date of transfer, it's generally due within three years of the transfer and before any subsequent transfer to a third party. A late claim can still be granted, but only going forward from the year it's filed.
2. File for the homeowners' exemption within one year of the transfer date. This is the step that proves the occupancy requirement, and it is the one most commonly missed.
3. Record the deed properly and file the Preliminary Change of Ownership Report with it. An unrecorded or incorrectly recorded transfer creates problems that surface years later.
4. Keep documentation of occupancy — voter registration, driver's license, utility accounts. If the Assessor questions the claim, this is what answers it.

Missing the one-year homeowners' exemption window doesn't forfeit the exclusion forever, but it doesn't get fixed retroactively either: the exclusion only starts with the year the exemption is finally filed, and every year before that is taxed on the full market value. In the Larkspur example, that's more than $10,000 in extra tax for each year of delay. The filing takes about twenty minutes.

Where the Transaction Itself Fits

Prop 19 planning is tax work — the province of a CPA or estate attorney. But when the transfer is a sale — a parent selling the family home to a child at an agreed price — it's a real estate transaction, and it still needs a contract, disclosures, title, escrow, and a properly recorded deed. Those are two different jobs, and families often assume that hiring someone for the first one covers the second.

When the buyer and seller are already family, there's no buyer to find and no property to market — which is most of what a traditional 5% commission pays for. On a $2.1 million Marin home, that commission would run roughly $105,000. FSBOTransact handles the contract, disclosures, escrow coordination, and closing on standard CAR forms for a flat $6,000, and makes sure the deed and Preliminary Change of Ownership Report are recorded correctly so the exclusion claim has clean ground to stand on. Families across the region can read more about flat-fee transactional real estate services in Marin and the North Bay.

A Marin family transfer done well looks like this: the CPA confirms the tax structure before a price is set, the transaction is documented on standard forms, the deed records correctly, and the exclusion claim and homeowners' exemption are filed inside their windows. Four steps, in that order. The expensive mistakes almost all come from doing them out of sequence — or from assuming the tax benefit arrives on its own.

Nothing here is tax or legal advice. Prop 19 outcomes turn on details specific to each family's circumstances, current inflation-adjusted thresholds, and how title is held. Review your situation with a CPA or estate attorney before committing to a structure.