Texas Family Code - FAM § 201.001. Appointment

(a) A judge of a court having jurisdiction of a suit under this title, Title 1, Chapter 45, or Title 4 may appoint a full-time or part-time associate judge to perform the duties authorized by this chapter if the commissioners court of a county in which the court has jurisdiction authorizes the employment of an associate judge.

(b) If a court has jurisdiction in more than one county, an associate judge appointed by that court may serve only in a county in which the commissioners court has authorized the associate judge's appointment.

(c) If more than one court in a county has jurisdiction of a suit under this title, Title 1, Chapter 45, or Title 4 the commissioners court may authorize the appointment of an associate judge for each court or may authorize one or more associate judges to share service with two or more courts.

(d) If an associate judge serves more than one court, the associate judge's appointment must be made with the unanimous approval of all the judges under whom the associate judge serves.

(e) This section does not apply to an associate judge appointed under Subchapter B  1 or C  2.