Texas Occupations Code - OCC § 1301.351. License, Endorsement, or Registration Required

(a) A person, other than a responsible master plumber, may not engage in plumbing unless:

(a-1) A person may not act as a responsible master plumber unless the person holds the appropriate license and meets the requirements for a responsible master plumber under this chapter.

(a-2) A person that advertises or otherwise offers to perform or provide plumbing must secure the services of a responsible master plumber.

(b) A person may not serve as a plumbing inspector unless the person is licensed under this chapter as a plumbing inspector.

(c) A license holder who is supervising and controlling under Subsection (a)(2) the work of a person engaged in the business of plumbing in the construction of a new one-family or two-family dwelling in an unincorporated area of the state must have training and management responsibility for, and shall review and inspect, the person's work.  The license holder is not required to provide continuous or uninterrupted on-the-job oversight of the person's work.

(d) A person who holds a license or registration issued under this chapter shall carry the license or registration on his or her person while engaged in plumbing.