Prop 19 for Move-Up Buyers

What Prop 19 does

The base year value transfer provisions of Prop 19 took effect April 1, 2021. They let an eligible homeowner transfer the existing, Prop 13-protected assessed value of their home (the factored base year value, or FBYV) to a replacement primary residence anywhere in California, instead of having the new home reassessed at its full purchase price.

Two things improved compared with the old Propositions 60 and 90. The transfer now works statewide, in all 58 counties. No county has to adopt a reciprocal ordinance first, unlike the old rules, where only a handful of counties opted in. And buying up no longer disqualifies you: under Prop 60 and 90, a replacement home priced above the threshold killed the claim outright and triggered a full reassessment. Under Prop 19, a more expensive replacement is allowed, and only the excess above the threshold gets added to your transferred base value.

Who qualifies

The base year value transfer is available to three groups:

• Owners 55 or older. You must be 55 or older when the original home sells, not merely by the time you buy the replacement. Only one spouse or registered domestic partner needs to meet the age test, but that person must be on title to both the original home at sale and the replacement at purchase.
• Severely and permanently disabled owners, at any age. A licensed physician must certify the disability on form BOE-19-DC, issued by the California State Board of Equalization (BOE).
• Victims of a wildfire or a Governor-declared natural disaster.

A few conditions apply across all three groups:

• The original home must have been eligible for the homeowners' or disabled veterans' exemption, meaning it was your principal residence. A rental, a second home, or an investment property does not qualify as the original property.
• You must own and occupy the replacement as your principal residence when you file the claim.
• The original home must actually be sold for consideration. Moving out is not enough.
• Only individuals can claim. A limited liability company (LLC), corporation, or partnership cannot. A present beneficiary of a trust can.

Owners 55 or older and severely disabled owners get three transfers in a lifetime, and the cap is tracked per person, so each spouse has their own three. Disaster victims are not subject to the three-transfer cap.

The timing rule that sets your threshold

You must buy or newly construct the replacement within two years of selling the original, either before or after the sale. Where you land inside that window sets the “equal or lesser value” threshold used in the math.

Full cash value is normally the sale price of the original home. For disaster victims it is the value the assessor determined immediately before the disaster.

Prop 19 did not delete the 100/105/110 tiers, and most explainers get this wrong. It changed what happens when you exceed them. Exceeding the threshold used to disqualify the claim entirely. Now the amount above the threshold is added to your transferred base value and the claim still stands.

The mechanics

Replacement at or below the threshold. Your existing factored base year value transfers over unchanged, so your tax bill on the new home stays close to where it was.

Replacement above the threshold, which is the move-up case this guide is about. Your new taxable base equals your old factored base year value plus the amount by which the replacement price exceeds the threshold.

New taxable value = old factored base year value + (replacement price − threshold)

You are not reassessed on the full purchase price, only on the increment above the threshold.

One adjustment to be aware of. If a January 1 lien date falls between the sale and the replacement purchase, the assessor applies an inflation factor of up to 2% per year to both the original home's full cash value and the transferred base value before running the math. A second-year purchase always crosses at least one lien date, so factoring always applies there.

A worked example

A 62-year-old homeowner sells for $900,000. Decades of Prop 13 protection left the factored base year value at $300,000. They buy a $1,100,000 replacement.

• Bought before the original sells (100% tier). Threshold = $900,000. Excess = $200,000. New taxable base = $300,000 + $200,000 = $500,000. At a blended effective rate of roughly 1.10%, about $5,500 a year.
• Bought eight months after the sale (105% tier). Threshold = $900,000 × 1.05 = $945,000. Excess = $1,100,000 − $945,000 = $155,000. New taxable base = $300,000 + $155,000 = $455,000, or about $5,005 a year.
• Bought in the second year after the sale. Inflation factoring enters here. Assuming a full 2% factor, the original's full cash value factors up to roughly $918,000, so the threshold is about $918,000 × 1.10 = $1,009,800, and the transferred base factors up to about $306,000. Excess is about $90,200. New taxable base lands near $396,000, or about $4,356 a year.

Compare either of the first two figures with a fresh reassessment of the full $1,100,000, which runs roughly $12,100 a year. The 105% case saves about $7,095 a year. Waiting longer widens the threshold and lowers the bill. These are illustrative figures using a hypothetical example and the site's blended estimate tax rate. They are not a quote for any specific property, and your assessor's inflation factor for a given year may be less than 2%.

The paperwork

The transfer is not automatic. You have to claim it.

• BOE-19-B for owners 55 or older
• BOE-19-D, plus BOE-19-DC, for severely and permanently disabled owners
• BOE-19-V for wildfire and natural disaster victims

File with the county assessor where the replacement home is located, not where the original was sold, and file within three years of the replacement purchase or completion of new construction.

Filing late does not forfeit the benefit, but it does forfeit retroactivity. Relief starts from the lien date of the year the claim is filed, so the savings for the earlier period are gone.

Buying the replacement first adds a timing wrinkle worth understanding. You pay full market-value property tax on the new home for the stretch between buying it and selling the original, and that stretch is not refundable. Taxes levied after the original sells but before your claim is approved are a different matter: those get cancelled or refunded down to the adjusted base value once the assessor processes the claim.

Sell the old home, or keep it as a rental?

The base value transfer only applies if you actually sell the original home. This is where move-up buyers get caught: keep the old home and rent it out (a common strategy) and you keep that property's own low tax basis, which is great for the rental's cash flow, but you cannot carry it forward. The new purchase gets a full, fresh reassessment with no Prop 19 offset.

The result is a real trade-off rather than a clear-cut answer. You can sell and transfer your tax base, or you can keep the rental's low basis and absorb the new home's full assessment, partly offset by rental income.

sounding's move-up mode is built to model both paths side by side. It treats a portion of expected rent (using the same 75% haircut a lender typically applies) as qualifying income if you keep the old home, so you can compare the combined monthly picture against selling and using a Prop 19 transfer instead. It shows you both numbers. It does not tell you which path is right for your situation, which depends on more than the tax math alone.

Common mistakes

• Assuming the transfer freezes your tax bill entirely: everything above the threshold is still reassessed.
• Assuming the claim files itself.
• Turning 55 between the sale and the purchase (too late for that sale).
• Selling a rental or second home and expecting it to serve as the original property. It cannot.
• Selling a duplex or multi-unit building: only the unit you occupied as your principal residence transfers, and the rest is reassessed at market value. An accessory dwelling unit (ADU) does not count against you here. A home with an ADU is not treated as multi-unit.

Related reading

Prop 19 is the seller side of the same Prop 13 reset that produces a supplemental tax bill on the buyer side. Worth understanding both directions if you are selling one home and buying another.