California's property tax system rests on two ballot measures that most homeowners have heard of but few fully understand: Proposition 13 from 1978, which keeps your annual tax bill low and predictable, and Proposition 19 from 2021, which changed the rules for moving your tax break and for passing property to your children. Together they explain why your neighbor might pay four times what you pay on a nearly identical house, and why inheriting the family home is no longer the tax gift it once was.
How Proposition 13 works
Proposition 13 does two things. First, it sets your base property tax at 1 percent of the property's assessed value, before local voter-approved additions like school bonds. Second, and more powerfully, it limits how much your assessed value can rise each year to 2 percent, or the rate of inflation, whichever is lower. This cap holds no matter how hot the market gets.
The key idea is that your assessed value is not your market value. When you buy, your assessed value is set at your purchase price. From then on it creeps up by at most 2 percent a year, even if the home doubles in market value. The assessed value only resets to full market value when the property changes hands. That is why long-term owners enjoy such low bills, and why a new buyer on the same block, taxed on today's purchase price, pays so much more for an identical house.
A few things do not trigger a reassessment, which surprises people: refinancing your mortgage, taking out a home equity loan, or moving your home into a revocable living trust where you remain the owner. Minor repairs under a modest annual threshold do not either. What does trigger it is a genuine change of ownership or new construction that adds value.
Proposition 19 and moving your tax base
Before Prop 19, older homeowners had limited ability to carry their low assessed value to a new home. Prop 19 expanded it. If you are 55 or older, severely and permanently disabled, or a victim of a wildfire or declared natural disaster, you can transfer your existing assessed value to a replacement home anywhere in California, and you can do it up to three times.
If your new home costs the same or less than the sale price of your old one, your old assessed value transfers unchanged. If the new home costs more, the difference is added to your transferred base, which is still far better than a full reassessment at the new purchase price. For a longtime owner sitting on a low base, this can mean the difference between an affordable move and staying put. Our Prop 19 tax-base transfer guide walks through how this plays out by region, and the Prop 19 calculator estimates the savings.
Proposition 19 and inherited property
This is where Prop 19 took something away. Under the old rules, a parent could pass a primary residence of any value to a child with no reassessment, plus up to 1 million dollars of assessed value in other property such as rentals. The child did not have to live in any of it. Families used this to hold real estate across generations at decades-old tax bases.
Prop 19 ended most of that. To keep a parent's low tax base on an inherited home today, the child must move in as their own primary residence within one year of the transfer and file for the homeowners' exemption. Even when they do, the protection is capped: the parent's factored base year value plus an inflation-adjusted amount, which is 1,044,586 dollars for transfers between February 16, 2025 and February 15, 2027. If the market value exceeds that sum, the excess is added to the new assessed value. Inherited rentals, vacation homes, and any property the child does not occupy are reassessed to full market value immediately.
The practical effect is significant. A family home bought decades ago and worth a few million dollars today can jump from a few thousand dollars a year in tax to five figures if the one-year occupancy rule is missed or the value sits far above the cap. If you are navigating an inherited property, our guide to selling an inherited house and probate sale guide cover the real estate side, and the paperwork can be prepared by Ashlar LDA at your direction.
What this means for planning
Prop 13 rewards holding property, and Prop 19 rewards planning around moves and inheritances. If you are older and considering a move, the portability benefit can make possible a move you thought you could not afford. If you expect to inherit a home, the one-year occupancy decision and the value cap deserve attention well before the transfer, because the difference between qualifying and not can be tens of thousands of dollars a year for as long as you own the home.
None of this is tax advice, and the details get specific quickly. A qualified estate planning attorney or CPA can model your situation. On the real estate side, from valuing a home you might sell to timing a move, Serve First Realty can help you see the picture clearly.