California Prop 19 Base Year Value Transfers: Forms and Deadlines

If you’re at least 55, severely and permanently disabled, or your home was destroyed by a wildfire or declared disaster, a California Prop 19 base year value transfer lets you carry your existing property tax assessment to a replacement primary residence anywhere in the state. The rule took effect April 1, 2021, and it matters most to longtime owners whose assessed value has been held down for decades by Proposition 13’s two percent annual cap. Moving without it can add thousands of dollars a year to your tax bill.

Who Qualifies

Three groups of homeowners are eligible, and each has its own claim form.

Homeowners age 55 or older at the time the original home is sold. If you co-own with a spouse or domestic partner, only one of you needs to meet the age threshold. Up to three lifetime uses.
Homeowners who are severely and permanently disabled, at any age. The disability standard is set in Revenue and Taxation Code Section 74.3 and covers conditions that substantially limit one or more major life activities. Up to three lifetime uses.
Victims of wildfire or natural disaster whose home sustained physical damage exceeding 50 percent of the market value of the land or improvements immediately before the disaster, in an area where the Governor declared a state of emergency. No statutory cap on the number of transfers.

Both the home you sell and the home you buy must be your primary residence, and you must have been eligible for the homeowners’ exemption or the disabled veterans’ exemption on the original property.¹

The Two-Year Window and Statewide Reach

Your replacement home must be purchased, or new construction completed, within two years of selling the original. The order doesn’t matter. You can buy first and sell second, or sell first and buy second, as long as both transactions land inside that two-year span.

There is no county restriction. Sell in San Diego, buy in Humboldt, and the transfer works the same. You file with the county assessor where the replacement home is located, not where the old one was.¹

How the Value Comparison Works

Whether your base year value transfers cleanly or gets an add-on depends on the price of the replacement home compared to the sale price of the original. The threshold shifts with timing:

Replacement bought before the sale: the replacement’s market value must not exceed 100 percent of the original’s sale price.
Replacement bought within one year after the sale: up to 105 percent.
Replacement bought in the second year after the sale: up to 110 percent.

Stay within the applicable percentage and the full base year value transfers with no increase. The 5 and 10 percent cushions exist because prices tend to move while you’re house-hunting.¹

When the Replacement Home Costs More

Exceeding the threshold doesn’t kill the transfer. It adds the excess to your base year value.

Say your original home sells for $800,000 with a base year value of $200,000, and you buy a replacement for $900,000 within one year. The 105 percent threshold is $840,000. The replacement exceeds that by $60,000, so the new assessed value becomes $260,000. Still far below the $900,000 market price.¹

If you’d bought that same $900,000 home before selling the original, the threshold would drop to 100 percent, or $800,000. The excess grows to $100,000, and the new assessed value becomes $300,000. Timing the purchase relative to the sale can change the tax outcome, so it’s worth running both scenarios before you commit.

Which Form to File

The form depends on your eligibility category:

BOE-19-B for homeowners at least 55 years old.
BOE-19-D for severely and permanently disabled homeowners.
BOE-19-V for wildfire and natural disaster victims.

All three are available from the California State Board of Equalization and from county assessor offices.²

Each form asks for the Assessor’s Parcel Numbers of both properties, the dates of sale and purchase, and Social Security numbers for all owners listed on both deeds. Disaster claims also require documentation of the Governor’s emergency declaration and evidence of the damage. The statutory framework is Revenue and Taxation Code Section 69.6.³

Filing Deadline and What Happens if You File Late

You have three years from the date you purchased or completed construction of the replacement home to file the claim. It goes to the assessor in the county where the replacement home is located.¹

Missing three years doesn’t permanently disqualify you, but late filing only takes effect starting in the year you actually file. Every year you spent paying full market-rate assessment before that is gone. Treat the three-year window as a hard deadline.

If you build a new home instead of buying an existing one, notify the assessor in writing within six months after construction is complete.

After the Assessor Approves the Transfer

Processing times vary by county, from a few weeks to several months. Once the claim is approved, you’ll receive a notice showing the new assessed value. If you paid at the full market-rate assessment during processing, the county typically issues a refund or credit. From then on your bill reflects the transferred base year value, plus any excess amount if you bought a more expensive home, and it continues to grow at Proposition 13’s cap of no more than two percent per year.⁴

One thing to expect regardless: buying a home in California triggers a supplemental property tax assessment, a one-time adjustment covering the period between your purchase date and the end of the current tax year. Even with an approved transfer, you may receive a supplemental bill based on the difference between the prior owner’s assessed value and your new assessed value. That’s separate from the regular annual bill.

A Note on Inherited Homes

Proposition 19 also changed how a parent’s low assessed value passes to a child, but those rules are separate from the senior, disability, and disaster transfer. An inherited family home only keeps the parent’s tax basis if the child moves in as a primary residence within one year and files for the homeowners’ or disabled veterans’ exemption, and even then the protection is capped at the parent’s factored base year value plus an inflation-adjusted amount ($1,044,586 for transfers between February 16, 2025, and February 15, 2027). The claim form is BOE-19-P.¹

Federal Capital Gains on the Sale of the Original Home

Proposition 19 handles your California property tax going forward. Selling the original home is a separate federal event. If the home has appreciated significantly, the profit can be subject to capital gains tax.

The IRS lets you exclude up to $250,000 of gain from the sale of a primary residence, or $500,000 if you file jointly with a spouse. You generally need to have owned and lived in the home for at least two of the five years before the sale. For most longtime California homeowners using Proposition 19, ownership and use aren’t the problem. The gain amount is.⁵

If you bought decades ago for $150,000 and sell for $1,200,000, the gain is roughly $1,050,000 before improvements and selling costs. A single filer would owe capital gains tax on $800,000 after the $250,000 exclusion. At 2026 federal rates, most of that falls in the 15 percent bracket, with the portion above $545,500 in taxable income taxed at 20 percent. Married couples filing jointly would exclude $500,000, leaving $550,000 subject to tax. Run the numbers before you list.

1
California State Board of Equalization. Proposition 19 – The Home Protection for Seniors, Severely Disabled, Families, and Victims of Wildfire or Natural Disasters Act
2
California State Board of Equalization. Property Tax Forms for Use by County Assessors Offices and Local Appeals Boards
3
Legal Information Institute. California Code of Regulations Title 18 – 462.540 – Change in Ownership – Base Year Value Transfers
4
California State Board of Equalization. California Proposition 19 Base Year Value Transfers for Seniors, Disabled, and Disaster Victims
5
Internal Revenue Service. Topic no. 701, Sale of Your Home