Texas Natural Resources Code - NAT RES § 142.003. Terms and Oath of Commissioners

(a) Each commissioner serves a term of two years and until his successor is appointed and has qualified.

(b) Each commissioner shall take the constitutional oath of office and shall also take an oath to faithfully perform his duties as commissioner.

(c) If a vacancy occurs in the office of commissioner, the original appointing officer shall appoint a successor to serve for the unexpired portion of the term.