Texas Tax Code - TAX § 42.09. Remedies Exclusive

(1) in defense to a suit to enforce collection of delinquent taxes; or

(2) as a basis of a claim for relief in a suit by the property owner to arrest or prevent the tax collection process or to obtain a refund of taxes paid.

(1) if the suit is to enforce personal liability for the tax, that the defendant did not own the property on which the tax was imposed on January 1 of the year for which the tax was imposed; or

(2) if the suit is to foreclose a lien securing the payment of a tax on real property, that the property was not located within the boundaries of the taxing unit seeking to foreclose the lien on January 1 of the year for which the tax was imposed.