Under Proposition 13, your assessed value can rise at most 2% per year while you own the home, no matter how fast market value climbs. Your tax bill is roughly that assessed value times the local tax rate, so in a typical year your property tax goes up around 2%, plus any voter-approved local assessments. One wrinkle: if a home's assessed value has been sitting below market for a while, the assessor can keep applying the full 2% each year until it catches up, so the increase can compound for several years running. That's still a modest, predictable climb rather than runaway growth, so it's generally not something to lose sleep over. The bigger reset happens when the property changes hands. A purchase usually triggers reassessment to the new market value, which becomes the new base for future increases. Rules and exceptions vary and can change, so confirm the current specifics with your county assessor or a local agent for your exact situation.