How to Transfer Your Property Tax Base Under Prop 19 in 2026

If you own a home in California, Proposition 19 is one of the property tax rules worth understanding before you move. The measure reshaped two corners of the state property tax system at once: how a low Prop 13 assessment can move with you to a new home, and how inherited homes are assessed. For longtime owners in the Conejo Valley, where values have held up well, the first of those can be the difference between a move that pencils and one that does not.

As of January 2026, the median home price in Westlake Village was $1,624,500, with an average sale price of $1,756,429. Thousand Oaks homes sold for a median of $1,012,500 in April 2026. At those prices, a reassessment to full market value is a serious number, which is why the Prop 19 transfer deserves a place in any move within the region.

What is Proposition 19 and How Does It Work in 2026?

Passed in November 2020 and in effect since 2021, this constitutional amendment still shapes decisions for homeowners, heirs and seniors in 2026. The part that matters for movers lets homeowners who are 55 or older, severely disabled, or victims of a wildfire or natural disaster transfer the low assessed value of their primary home to a newly purchased or newly built replacement principal residence. The tax base can go to a property anywhere in the state, and age and disability claimants can use the benefit up to three times.

The mechanics are simple. Under Proposition 13, a home bought for $180,000 in 1995 with no major improvements might carry a 2026 factored base year value somewhere around $290,000, even if it would sell today for $1.4M. That gap between assessed value and market value is what Prop 19 lets you keep.

Before Prop 19, a 55-year-old selling a longtime home in Los Angeles County faced strict limits when moving to a different county. Only 10 California counties accepted incoming base transfers from elsewhere. Prop 19 removed those county lines entirely.

For families weighing a move from Los Angeles to the Conejo Valley, that change matters a great deal. Consider a homeowner who bought near Wildwood Regional Park in Thousand Oaks 25 years ago. That low tax base can now move with them to a home in Westlake Village, a few minutes from dinner at ONYX.

How Much Can You Save by Transferring Your Tax Base?

This example assumes the replacement home costs no more than the original home sold for. If you pay more, the difference is added to your transferred base, which trims the savings. Purchase prices run highest in Westlake Village's premium communities, so the math there deserves a careful look before you write an offer.

How Does the Transfer Work When You Sell Your Home?

When you sell your primary residence and buy a replacement home, the Prop 19 claim is handled by your county assessor, not your escrow company. You file a claim form, generally BOE-19-B for owners 55 and older, with the assessor in the county where the replacement home sits. Timing matters: the replacement home must be purchased or newly built within two years of the sale of your original home, either before or after that sale, and the claim should be filed within three years of the purchase or completion date to get full retroactive relief. Inherited homes fall under a different part of Prop 19, with a separate claim form and its own deadlines, so do not assume the same window applies without checking with the assessor or your attorney.

For Conejo Valley sellers moving within Ventura County, the process is often smoother than a move across county lines, since the assessor already has your original property's records. Either way, confirm eligibility before removing contingencies on a replacement purchase, since a denied transfer can add over $10,000 a year to a household's tax bill. Your agent, licensed through the California Department of Real Estate, can help you prepare, but only the assessor rules on the claim. Statewide, median existing home price data from the National Association of Realtors shows California homes selling well above the national median, which makes the transfer especially valuable for longtime owners sitting on a low assessed value.

The table below shows how the transfer works in some of the most common local moving scenarios we see across Thousand Oaks, Westlake Village, Newbury Park, and Agoura Hills. Savings are estimated at a 1.1% rate and assume the replacement home costs no more than the original home sold for.

The savings can be substantial, particularly in high-value markets like the Conejo Valley. Most homeowners in Ventura County pay an effective property tax rate of roughly 1.1% to 1.3% of assessed value, so every $100,000 of assessment you avoid is worth $1,100 to $1,300 a year. Your CPA can tell you how that interacts with the rest of your tax picture.

Here is an illustration. A homeowner purchased a property in 1998 for $350,000. Under Prop 13's 2% annual cap, their 2026 factored base year value would be in the neighborhood of $560,000. Without Prop 19, buying a $1,624,500 home in Westlake Village would trigger reassessment at the full purchase price; with it, the $560,000 base can come along, subject to the price difference rule noted above.

Published countywide figures put the median property tax bill in Ventura County at $3,372 per year on a median home value of $568,700, or about 0.59%. Treat that number with care: it reflects older, Prop 13 protected assessments across the whole county, not what a buyer pays after a purchase at today's prices.

For move-up buyers looking at Westlake Village's premium communities, the Prop 19 benefit grows with the purchase price. Savings in the $10,000 a year range can offset a meaningful slice of a larger mortgage payment.

Who Qualifies for Prop 19 Tax Base Transfers?

Eligibility runs on three parallel tracks: you are 55 or older when the original home sells; you are severely and permanently disabled, regardless of age; or you are the victim of a wildfire or natural disaster declared by the Governor, regardless of age.

The age test is simple, but the date matters: the claimant must be at least 55, or severely disabled, on the date the original property sells. Disability claimants also submit a Certificate of Disability signed by their physician, and the move itself must be made to accommodate or alleviate the disability.

Disaster victims face different rules. For Governor declared disaster victims, there is no limit on the number of times the benefit can be used. Given California's wildfire history, this provision comes up more often than it used to for families relocating to the Conejo Valley.

The property requirements are equally specific. The original property must have been owned and occupied as the claimant's principal residence and must be sold before a claim is filed. The replacement property must be the claimant's principal residence when the claim is filed, and the claimant must be eligible for the homeowners' exemption or the disabled veterans' exemption on it.

For families exploring move-up opportunities in the Conejo Valley, sorting out these requirements early prevents expensive surprises. Many eligible owners also do not realize the benefit is reusable: up to three times for age and disability claimants.

How Do You Apply for a Prop 19 Tax Base Transfer?

The application comes down to the right form and the right deadline. Use BOE-19-B for the age 55+ track, BOE-19-D for disability, or BOE-19-V for disaster victims, and file with the county assessor where the replacement property is located.

For Conejo Valley replacement homes, that means working with the Ventura County Assessor. The timing window is strict: the sale of the original home and the purchase of the replacement must fall within two years of each other, in either order, and the claim then goes to the assessor.

The documentation requirements vary by qualifying category:

Age 55+ applicants: a completed BOE-19-B form, proof of age (driver's license or birth certificate), and a homeowners' exemption claim for the new property.

Disability applicants: a completed BOE-19-D form, a physician-signed Certificate of Disability, and evidence that the move accommodates the disability.

Disaster victims: a completed BOE-19-V form, documentation of the disaster damage, and a reference to the Governor's disaster declaration.

The deadline to remember: file within three years of purchasing or completing the replacement home to have the lower base applied back to the date of purchase. File later and relief generally runs only from the year you file, so the lost years are gone for good. On a transaction this size, that is worth a conversation with the assessor's office or your CPA before you close.

For anyone planning a move within the region, including owners who also hold rental property in Thousand Oaks or Westlake Village, remember the transfer applies only to your primary residence, so coordinating the sale, purchase and filing dates is what makes it work.

What Are the Most Common Mistakes When Using Prop 19?

The most costly errors revolve around timing and property use. The sale and the replacement purchase must fall within two years of each other, and the claim has to be filed with the assessor; neither step happens automatically through escrow.

Mistake #1: Missing the principal residence requirement

The replacement property must be your principal residence when the claim is filed, and you must be eligible for the homeowners' exemption on it. A vacation home or rental does not qualify, even if you intend to move in later.

Mistake #2: Getting the two-year window wrong

The replacement home must be purchased or newly built within two years of the sale of the original home. Buying first and selling second is allowed, but the clock still runs: if the original home does not sell within two years of the replacement purchase, the transfer is lost.

Mistake #3: Forgetting the three-use limit

Age and disability claimants can use the transfer up to three times in a lifetime; Governor declared disaster victims have no limit. Spending one of those three on a short-term move is a real cost, so think about where you expect to be in ten years before you file.

Mistake #4: Thin documentation on disability claims

The move must be made to accommodate or alleviate the disability. Having a qualifying disability is not enough on its own; your documentation needs to connect the move to that purpose.

These mistakes get expensive in a market like the Conejo Valley, where the savings can exceed $10,000 a year. If your move involves inherited property or a trust, loop in your CPA or estate attorney early; the rules for inherited homes differ from the transfer rules covered here.

Frequently Asked Questions About Prop 19 Tax Base Transfers

How many times can I use the Prop 19 tax base transfer?

Homeowners who are 55 or older or severely disabled can use the transfer up to three times in their lifetime; wildfire and disaster victims have no limit. Each transfer must involve a primary residence, and the claim is filed with the county assessor where the replacement home is located, ideally within three years of the purchase or completion date.