Exemptions reflect the owner on January 1st. If you purchased a home after January 1st the exemption in place was for the previous owner. You must file an exemption application.
Exemptions can also be removed if the district sends a letter requesting reapplication. If an exemption or exemptions are removed the homeowner may reapply with appropriate supporting documentation. If the new application is submitted no later than one year after the taxes are due, the exemption will be effective in the original qualifying year. If the application is submitted more than one year after the taxes are due the exemption will apply to the current year and will not be effect for the prior year(s).
A homeowner is entitled to an exemption on his or her primary residence as provided for in the Texas Property Tax Code. If the homeowner has more than one homestead exemption the erroneous exemption will be removed, the Texas Property Tax Code requires that the district calculate the taxes owed for the last 5 years or period of time the erroneous exemption was in place.