Laura,
The estimated Ad Valorem tax rate .01155. To estimate the tax on a particular parcel multiply the sales price by that amount. Then add to that the flat parcel taxes for the area. In this case it would and additional $1198.52 to the annual tax bill. For example, a good estimated annual tax on a house selling for $500,000 in Kensington would be:
Ad valorem $5,775.00
Parcel tax $1,198.52
Total $6,973.52

Hi Laura,

To estimate annual property taxes use 1.25% X Sales Price

CA's Proposition 13 limits the taxation of property to 1.2% of a property’s assessed value (as a Buyer this is the sales price), PLUS any special assessments and improvement bonds approved by the voters. Property tax increases are limited to a 2% increase in the assessed value of the property per year.

Best, Steve