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Guide

Prop 19: Moving Your Tax Base (55+)

By Karla I. Vasquez, REALTOR® · Keller Williams Realty Danville · Reviewed October 2026

Quick answer

Under Proposition 19, California homeowners who are 55 or older can sell their primary residence and transfer its taxable value (their "tax base") to a replacement home anywhere in California, up to three times. The replacement must be bought or built within two years before or after the sale. If the new home costs more, part of the difference is added to your transferred value.

Who qualifies for a Prop 19 base year transfer?

According to the State Board of Equalization (BOE), Prop 19 base year value transfers became operative April 1, 2021. The same benefit also applies to severely disabled homeowners and victims of wildfire or other governor-proclaimed natural disasters, each with their own form.

For the 55+ transfer, the BOE's information sheet lists these key requirements:

  • Age: You are at least 55 (if married, only one spouse needs to meet the age requirement) when the original home is sold.
  • Primary residence: Both the original and the replacement home must be your principal residence and qualify for the homeowners' (or disabled veterans') exemption.
  • Timing: Buy or build the replacement within two years before or after selling the original.
  • A real sale and purchase: Both transactions must involve consideration (a sale, not a gift).
  • Up to three transfers over your lifetime.
  • Anywhere in California: The replacement can be in any county.

How does the value comparison work?

Here's where it gets technical. To keep your full tax base, the replacement's market value must be no more than:

  • 100% of the original home's value, if you buy the replacement before you sell;
  • 105%, if you buy within the first year after selling;
  • 110%, if you buy within the second year after selling.

If the new home is worth more than that limit, you don't lose the benefit. Instead, the amount above the limit is added to your transferred base year value. The BOE gives an example: a $700,000 original home sold, a replacement bought within the first year for $800,000. The 105% limit is $735,000, so $65,000 is added to the transferred value.

Good to know: If you buy the replacement before the original sells, the BOE notes you'll pay taxes on the new home at its full value until the original is sold and the transfer applies.

How and when do I file?

  • Form: BOE-19-B, Claim for Transfer of Base Year Value to Replacement Primary Residence for Persons at Least Age 55 Years.
  • Where: File with the Assessor in the county where the replacement home is located. For a Contra Costa replacement home, that's the Contra Costa County Assessor, which posts the forms on its Prop 19 page.
  • When: Within three years of buying or completing construction on the replacement. Late claims are accepted, but relief starts with the year you file.

Prop 19 also changed parent-child transfers

Prop 19 narrowed the old parent-child exclusion. The BOE explains that it now generally applies only to a family home that becomes the child's principal residence (or a family farm), with a value limit: the factored base year value plus an adjusted $1 million amount, currently $1,044,586 for transfers from February 16, 2025 to February 15, 2027. If you're thinking about leaving your home to your children, talk with an estate planning attorney and a tax professional.

Karla's tips

  • Run the numbers before you list. Ask the Assessor for your current factored base year value and compare it with likely replacement prices. Timing your purchase can change the 100/105/110% limit.
  • Downsizing doesn't have to mean "smaller and older." With KCK Construction & Remodeling, I can help you look at single-level homes or homes that can be adapted for aging in place, and estimate what a remodel would cost.
  • Count your transfers. You only get three. If you made a base year transfer claim in the past, ask the Assessor how it affects you.
  • Keep both closing statements. You'll need sale and purchase details when you file the claim.
  • Atiendo en español. Many of my senior clients prefer to review the steps in Spanish. Call (510) 677-8695.

En español: lo básico

Con la Proposición 19, los propietarios de 55 años o más pueden vender su residencia principal y llevar su base de impuestos a otra casa en cualquier parte de California, hasta tres veces. Debe comprar o construir la nueva casa dentro de dos años antes o después de la venta. Si la nueva casa vale más del límite (100%, 105% o 110%, según cuándo compre), la diferencia se suma a su valor transferido. El formulario es el BOE-19-B y se presenta ante el Asesor del condado donde está la nueva casa, dentro de tres años.

Sources

General information only, not legal, tax or financial advice. Rules and fees change; confirm with the County, the Board of Equalization, your tax professional or an attorney. Karla I. Vasquez is a REALTOR® and Registered LDA, not an attorney.