Prop 19 explained: keep your tax base when you sell

Last updated October 6, 2026

By Kurt Mellinger, Principal Agent, Ascension Estates at Equity Union Real Estate. DRE #02238998.

If you are 55 or older, Proposition 19 lets you take your low property tax basis with you when you move, to a replacement home anywhere in California. If you bought decades ago, that basis is probably a fraction of what a new buyer would pay on the same house today, so it is worth real money every year you own the next one. The rules have deadlines, and missing one costs the benefit permanently.

What Prop 19 actually does

Before Prop 19, moving to a new home in California generally meant your property taxes were reassessed at the new home's full market value, no matter how low your old tax basis was. For a longtime owner, that could mean a tax bill several times higher, permanently.

Proposition 19, passed in 2020, changed this for homeowners 55 or older, severely disabled homeowners, and victims of wildfire or natural disaster. It lets you carry your existing, lower property tax basis to a replacement home anywhere in California, even if the new home costs more than the one you sold.

How to transfer your property tax base under Prop 19

• You must be 55 or older (or severely disabled, or a qualifying disaster victim) at the time you sell your original home.
• The replacement home can be anywhere in California, not just the same county, and can cost more than your original home.
• If the new home is worth more, the assessor compares it with your old home's market value at the sale. Buy before you sell and the line sits at 100% of that value. Buy in the first year after the sale and it moves to 105%, and in the second year to 110% (source: Revenue and Taxation Code section 69.6). Only the amount above the line is added to your transferred base.
• You can use this up to three times in your lifetime if you qualify by age or disability. The three time limit does not apply to wildfire and natural disaster victims.
• Timing matters. You generally must purchase the replacement home within two years of selling the original, whether you buy first or sell first.
• File the claim. For owners 55 and older it is form BOE-19-B, filed with the assessor in the county of the new home within three years of buying it.

Sources: Revenue and Taxation Code section 69.6, and the California State Board of Equalization's Proposition 19 page at boe.ca.gov/prop19, both read October 6, 2026.

Already have a replacement home in mind? See what the actual monthly payment looks like with Mortgage vs Rent, our free buyer calculator.

Where owners lose the benefit

The rules around sequencing and deadlines are unforgiving. Buy or sell outside the two year window and the transfer is gone for that move. Misjudge how the value line is calculated and the new tax bill comes in higher than you planned. File the claim after the three year deadline and the assessor can still grant it, but only from the lien date of the year you file, so the savings for the years before are lost. This is exactly the kind of detail that decides whether selling now or waiting is the better financial move, and it is rarely explained clearly before someone lists their home.

This is general information. It is not tax or legal advice. Confirm your specific numbers and timing with a qualified tax professional or your county assessor before you act.

The only way to know your real numbers, your current tax basis, your projected transfer, and what a sale nets you after every fee, is to see them laid out for your specific home.