Property tax is the recurring value tax, kind of a wealth tax while you hold a property, and prop 13 does shield much of the appreciated value from this. A new homeowner might be paying 1-2% of market price per year, while an elderly neighbor might pay 1-2% of an assessed value that is closer to a market value from 20+ years ago. The assessment does increase at a very slow rate, and in larger jumps with remodeling or other improvements.

At the sale, the appreciation becomes realized as capital gains income. There are some rules making a portion of gains tax-exempt for a typical homeowner, but the remainder of a large appreciation is taxed as income. There can also be a sales/transfer tax on the transaction, which is of a comparable rate to the annual property tax rate.

The third significant event is inheritance, where the house could pass to an heir without a sale and have its basis updated to current value. This is when the appreciated gains can really go untaxed.