Prop 19 in Marin: What It Protects and What It Costs

Key Takeaways

• Prop 19 in Marin works in two opposite directions. One half rewards homeowners over 55. The other half costs their children.
• Homeowners 55 and older can carry their property tax base to a new home up to three times, anywhere in California, within two years of selling. On a long-held Marin home, that benefit often exceeds the price gap between two properties.
• A child who inherits a Marin home and does not move in loses the parent’s tax base entirely. The county reassesses the property at full market value.
• Even a child who does move in faces a cap. The exclusion equals the parent’s factored base year value plus $1,044,586 through February 15, 2027.
• The rules are stable. A third repeal attempt failed to reach the November 3, 2026 ballot.

What Prop 19 in Marin actually does

Proposition 19 changed two California property tax rules. It lets homeowners aged 55 and older transfer their existing assessed value to a new primary residence up to three times, anywhere in the state. It also requires a child who inherits a home to live in it, and caps the protection, or the county reassesses the property at market value.

Those two halves pull against each other, and most coverage treats them as one policy. For a Marin family, they are separate decisions with separate deadlines.

Here is why the stakes run higher here than almost anywhere else. A family buys in Kentfield or Ross in the eighties. Decades later they pay roughly four thousand dollars a year on a home worth four million. Proposition 13 created that gap. Prop 19 decides whether it survives a move, or a death in the family.

Prop 19 and homeowners over 55: carrying your tax base

If you are 55 or older, severely and permanently disabled, or a victim of wildfire or natural disaster, you may transfer the assessed value of your primary residence to a replacement primary residence. You may do it up to three times, anywhere in California, within two years of the sale.

Each of those three terms is an expansion. The prior rules allowed one transfer, and only inside your own county or the handful that accepted incoming transfers. As a result, Marin homeowners used to forfeit the benefit the moment they considered Sonoma or Santa Barbara. They no longer do.

When the replacement home costs less

Consider a couple who bought in Larkspur in 1994. Their factored base year value is $450,000. They sell for $3,000,000 and buy a single-level home in Marin for $2,400,000 within the year.

The replacement costs less than the original sold for. Therefore the base year value transfers intact. Their new assessed value is $450,000, not $2,400,000. At the 1% Proposition 13 base rate, that is roughly $4,500 a year instead of $24,000. Local assessments push both bills higher, but the gap persists for as long as they own the home.

When the replacement home costs more

You keep most of the benefit. First, adjust the original home’s sale price upward based on timing: 100% if you buy before the original sells, 105% within the first year after, 110% in the second year. Then only the amount above that adjusted figure joins your transferred base.

Take the same Larkspur couple. They sell for $3,000,000 and buy for $4,000,000 in the first year. The adjusted original value is 105% of $3,000,000, or $3,150,000. The excess is $850,000. Added to their $450,000 base, the new assessed value becomes $1,300,000 on a four million dollar home.

That runs roughly $13,000 a year at the base rate, against $40,000 had the county assessed the home at its purchase price. In other words, they moved up a million dollars and kept most of the advantage.

Notice what the formula rewards. Buying before you sell preserves the most value. Waiting into the second year gives you a softer threshold but less room on the deadline. Consequently the sequence of a move carries a real number, and it is one of the few places where transaction order matters more than negotiation.

The filing deadline

File form BOE-19-B with the Marin County Assessor within three years of purchasing or completing the replacement home. File later and relief still applies, but only from the year you file forward. The intervening years are lost.

Prop 19 and inherited homes in Marin: what changed in 2021

This half changed on February 16, 2021, and it changed severely.

Inherited property	Before February 16, 2021	Under Prop 19 today
Parent’s primary residence	Excluded from reassessment at any value	Excluded only if the child moves in, and only up to the parent’s base plus $1,044,586
Second home or vacation property	Excluded up to $1 million of assessed value	Reassessed at full market value
Rental or investment property	Excluded up to $1 million of assessed value	Reassessed at full market value
Family farm	Excluded	Still excluded, subject to the same cap

The home has to be somebody’s residence

The property must have served as the parent’s principal residence, and the child must make it their own principal residence. The proof is a homeowners’ exemption filed within one year. A second home, a rental, or a house the children plan to hold and sell draws a full reassessment at market value.

The $1,044,586 cap, worked through

Take a Ross home with a factored base year value of $400,000 and a market value of $4,000,000 at the parent’s death. A daughter moves in, files the homeowners’ exemption within the year, and files form BOE-19-P.

In that case the exclusion covers $400,000 plus $1,044,586, or $1,444,586. The remaining $2,555,414 goes onto the base. Her new assessed value is $2,955,414, which runs roughly $29,500 a year at the base rate against the $4,000 her parents paid. She did everything correctly and her tax still rose sevenfold.

Now suppose she does not move in. She keeps the house, rents it, and visits at Christmas. The county reassesses the home at $4,000,000, roughly $40,000 a year. Moving in was worth about ten thousand dollars a year to her, indefinitely.

This is the arithmetic that quietly forces Marin families to sell homes they fully intended to keep. Importantly, the cap adjusts for inflation every two years, so the figure above holds only through February 15, 2027.

The filing deadlines

Form BOE-19-P covers parent to child. Form BOE-19-G covers grandparent to grandchild. Either is due within three years of the transfer, or before the property passes to a third party, whichever comes first. The homeowners’ exemption is a separate claim, due within one year of the death or transfer. Both are required, and missing either one forfeits the exclusion.

Did Prop 19 get repealed in 2026?

No. Initiative 25-0017 would have restored the pre-2021 treatment of inherited homes and removed the value cap. It cleared for signature gathering on November 7, 2025, but it did not qualify. When the California Secretary of State certified the November 3, 2026 ballot on June 25, 2026, no measure concerned property tax on inherited property.

The reason is straightforward. The Legislative Analyst’s Office estimated in October 2025 that the measure would cost local governments and schools roughly $1 billion a year initially, and about $2 billion annually over time, split evenly between schools and local agencies.

Three repeal efforts have now failed. Plan around the rules as written.

What I would do if this is your situation

If you are over 55 and have owned your Marin home more than fifteen years, find your factored base year value before anything else. Most owners have never looked. That figure, rather than the sale price, determines what a move actually costs, and it frequently changes which homes sit within reach.

If you are planning an estate around a Marin property, raise it with your children now. The question of which child, if any, will genuinely live in the house decides the entire tax outcome. The conversation is difficult. The alternative is more so.

If you have already inherited, check the filing dates today. The three-year window and the one-year exemption window are where families lose the benefit through nothing more than inattention.

I am glad to talk through how any of this intersects with a specific property or timeline. Start a conversation with me directly, or request a current valuation of your Marin home. If a sale looks likely, my guide to selling a luxury home in Marin covers what follows, and the relocation guide to Marin towns is useful if the replacement property is local.

This is general market commentary, not tax or legal advice. Proposition 19 is constitutional law with ongoing administrative guidance, and circumstances vary considerably. Speak with a California estate attorney or CPA before acting, and confirm current figures with the California State Board of Equalization or the Marin County Assessor.

Frequently Asked Questions

What is Proposition 19 in California?

Proposition 19 is a 2020 constitutional amendment that changed two property tax rules. It expanded base year value transfers for homeowners 55 and older, severely disabled homeowners, and disaster victims, effective April 1, 2021. It also narrowed the parent to child reassessment exclusion, effective February 16, 2021.

How many times can I transfer my property tax base under Prop 19?

Up to three times, if you are 55 or older or severely and permanently disabled. The replacement home may sit anywhere in California. You must purchase or complete it within two years of selling the original primary residence.

What happens if my replacement home costs more than the one I sold?

You keep most of the benefit. The adjustment depends on timing: 100% if you bought before the sale, 105% in the first year after, and 110% in the second year after. Only the amount above that adjusted figure joins your transferred base year value.

Do my children have to live in my Marin home to keep my property tax base?

Yes. Since February 16, 2021, the exclusion applies only to a family home that was the parent’s principal residence and becomes the child’s principal residence, evidenced by a homeowners’ exemption filed within one year. A rental, a second home, or an investment property draws a full reassessment.

How much is the Prop 19 parent to child exclusion worth?

The exclusion equals the parent’s factored base year value plus $1,044,586 for transfers between February 16, 2025 and February 15, 2027. The figure adjusts for inflation every two years. Market value above that combined figure joins the new base year value.

Why does Prop 19 in Marin matter more than elsewhere in California?

Because the gap between assessed value and market value runs unusually wide here. Marin’s median sale price reached $1,650,500 in August 2026, while homes held since the eighties often carry base year values under half a million dollars. A wider gap makes the transfer worth more and exhausts the inheritance cap faster.

Which Prop 19 forms do I file in Marin County?

File BOE-19-B for a base year value transfer, within three years of buying or completing the replacement home. File BOE-19-P for parent to child, or BOE-19-G for grandparent to grandchild, within three years of the transfer or before the property passes to a third party. All go to the Marin County Assessor.

About Lauren Hamblet

Lauren Hamblet is a luxury real estate advisor with Coldwell Banker Global Luxury, serving Marin County, San Francisco, and the broader Bay Area. Twenty-five years across the Ross Valley and southern Marin, alongside four generations of San Francisco family history, have shaped her quietly sophisticated, globally informed approach. Learn more about Lauren or read answers to common Marin real estate questions.

Lauren Hamblet
Luxury Property Specialist | Coldwell Banker Global Luxury
(415) 233-1659 | lauren.hamblet@cbnorcal.com
laurenhamblet.com | DRE 01324847

Last updated: October 5, 2026