There are several factors that affect your tax rate:
Your property's taxable value. The Taxable Value of a property is adjusted each year based on the Consumer Price Index (CPI) and other factors. An increase in taxable value will result in an increase in your taxes.
A millage increase. Your tax bill includes City taxes, County taxes and school taxes. Since your tax rate is based on your home's Taxable Value multiplied times the millage rate, a millage increase will cause your taxes to go up.
You purchased a new home. Proposal A, which was passed in 1994, places an annual cap on the growth of property tax assessments; however, when the home is sold, the cap comes off and the assessment reverts to the State Equalized Value (SEV).