Dave's correct in stating 1.25%. However, to be more specific, all homes pay a "basic" tax of 1% of the assessed value. For example, if you bought your house for $100,000, the basic tax for the first year (not including supplemental taxes) would be $1,000. Then depending on your town or city, there will be additional bonds, assessments or taxes. The average, or rule of thumb, is .25%. With time, properties appreciate in value. Prop 13 limits the tax collectors from increasing your "assessed" value more than 2% a year.
You may be reading about homeowners who bought at the peak of the market applying to have their home "re-assessed" to lower their tax bill.