http://www.austintitle.com/downloads/TexasHomesteadExemption.pdf

An exemption removes part of the value of your property from taxation and lowers
your tax bill. In order to qualify for the online Homestead Exemption filing,
the property owner must have owned and occupied the property as of
January 1st of the current tax year.

This property must also be your principal residence and you may not
claim another homestead on another piece of property. Property purchased
after January 1st of the tax year would not qualify for the online homestead
exemption filing for the current year. Requirements are a state issued Driver's
License or Identification card showing your current physical address .

You must file an Application for Residential Homestead Exemption with the
county appraisal district between January 1 and April 30 of the tax year -- up
to one year after you pay your taxes. During the year, if you turn 65 or become
disabled, you must apply for the 65 or older or disabled exemption no later
than one year from the qualification date. Once you receive the exemption, you
do not need to reapply unless the chief appraiser sends you a new application.
In that case, you must file the new application.