Tex. Elec. Code § 144.006
(a) Except as otherwise provided by law, a declaration of write-in candidacy must be filed not later than 5 p.m. of the fifth day after the date an application for a place on the ballot is required to be filed in an election in which:
Added by Acts 2003, 78th Leg., ch. 1316, Sec. 35, eff. Sept. 1, 2003.
Acts 2005, 79th Leg., Ch. 1109 (H.B. 2339), Sec. 6, eff. September 1, 2005.