Sec. 42.09.  REMEDIES EXCLUSIVE.  (a)  Except as provided by Subsection (b) of this section, procedures prescribed by this title for adjudication of the grounds of protest authorized by this title are exclusive, and a property owner may not raise any of those grounds:
(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.
(b)  A person against whom a suit to collect a delinquent property tax is filed may plead as an affirmative defense:
(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.
(c)  For purposes of this section, "suit" includes a counterclaim, cross-claim, or other claim filed in the course of a lawsuit.
Acts 1979, 66th Leg., p. 2311, ch. 841, Sec. 1, eff. Jan. 1, 1982.  Amended by Acts 1987, 70th Leg., ch. 53, Sec. 1, eff. May 6, 1987.