The Texas State Code, Section 11.13: Residence Homestead explains the Texas Homestead Exemption.
The code requires public school districts give a $25,000 exemption on residence homesteads that are located within their districts. A residence homestead must be the primary residence.
The code also provides that a homeowner is entitled to an exemption of up to 20% of their appraised property value and at least $5,000 and no less. Also, Counties must offer an additional, separate homestead exemption of $3,000, if the county collects flood-control or farm-to-market taxes from residents.