Tex. Transportation Code § 452.601: ADDITION OF TERRITORY BY MUNICIPAL ANNEXATION.

(a) When a municipality that is part of an authority annexes territory that before the annexation is not part of the authority, the annexed territory becomes part of the authority.

(b) When a contiguous municipality annexes additional territory, the annexed territory becomes a part of the subregional authority created by the contiguous municipality.

(c) Except for Subsection (b), this subchapter does not apply to an authority created by a contiguous municipality.

Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.