Tex. Property Code § 92.261: LANDLORD'S DEFENSES.

The landlord has a defense to liability under Section 92.259 if:

(1) on the date the tenant gives the notice required by Section 92.259 the tenant has not paid all rent due from the tenant; or

(2) on the date the tenant terminates the lease or files suit the tenant has not fully paid costs requested by the landlord and authorized by Section 92.258.

Acts 1983, 68th Leg., p. 3653, ch. 576, Sec. 1, eff. Jan. 1, 1984.