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California homeowner guide · Reviewed September 6, 2026Proposition 8 vs. Proposition 13. Two rules, one tax bill.
Proposition 13 sets the normal ceiling for a California property's assessed value. Proposition 8 is the temporary off-ramp when current market value falls below that ceiling. The two rules are often discussed together, but they solve different problems.
What Proposition 13 does
Proposition 13 generally starts with a base-year value, usually the market value at a change in ownership or completion of new construction. That base value is adjusted each year by the lower of the California Consumer Price Index change or 2 percent. The result is often called the factored base-year value.
What Proposition 8 does
Proposition 8 applies when the property's January 1 market value is below its factored base-year value. In that situation, California law calls for the lower value to be enrolled. The reduction is tied to current market conditions, so it is reviewed again each year.
Why the 2 percent rule may not apply after a reduction
This is the part that surprises people. A property in Proposition 8 decline-in-value status is assessed from current market value, not from the normal factored base-year value. Its assessment may therefore rise by more than 2 percent as the market rebounds. The value still cannot go above the property's factored base-year value unless a separate reassessment event occurs.
A lower assessment is not permanent by default. It may last one year or several. Check the assessed value every year while the property remains below its factored base-year value.
Example without the false precision
Suppose a property's factored base-year value is higher than the sales evidence supports on January 1. A Proposition 8 review may reduce the enrolled value for that roll. If the market rises next year, the assessor can raise the enrolled value to reflect the new market value, even by more than 2 percent, until it catches back up to the factored base-year value.
That is why an appeal should focus on the valuation date, the property, and the available comparable sales. It is not an argument that California's tax rate is unfair or that the homeowner paid too much tax in a prior year.