Tex. Property Code § 92.053: BURDEN OF PROOF.

(a) Except as provided by this section, the tenant has the burden of proof in a judicial action to enforce a right resulting from the landlord's failure to repair or remedy a condition under Section 92.052.

(b) If the landlord does not provide a written explanation for delay in performing a duty to repair or remedy on or before the fifth day after receiving from the tenant a written demand for an explanation, the landlord has the burden of proving that he made a diligent effort to repair and that a reasonable time for repair did not elapse.

Acts 1983, 68th Leg., p. 3633, ch. 576, Sec. 1, eff. Jan. 1, 1984.