Apprentice plumber.
An apprentice plumber is any person other than a master plumber or a journeyman plumber, who as his principal occupation is engaged in learning and assisting in the installation of plumbing and shall work only in the presence of and directly under the supervision of a journeyman plumber or a master plumber.
Journeyman plumber.
A journeyman plumber is any person other than a master plumber, who as his principal occupation is engaged in the practical installation of plumbing and gas fitting, and who shall work under the supervision of a licensed master plumber, and holds a license as a journeyman plumber that has been issued from the state board of plumbing examiners.
Master plumber.
A master plumber is any person having a regular place of business, who is skilled in the plumbing, superintending and the practical installation of plumbing and gas fitting, and familiar with the laws, rules and regulations governing the same and who is licensed under the terms of state law. A master plumber holds himself out to the public as one who contracts for and causes to be done such plumbing and gas fitting work. A master plumber shall employ licensed journeymen plumbers to perform all plumbing or gas fitting work that is done under his supervision by others, except that he may employ apprenticed plumbers as helpers to journeyman plumbers.
(1965 Code, sec. 15-44)
Before any person shall do any work or make an connections with the sewer system, or do any plumbing work connected or intended to be connected with the sewer, he shall be licensed as provided in Senate Bill No. 188, “The Plumbing License Law of 1947,” passed by the 50th Legislature, being article 6243-101 of Vernon’s Annotated Civil Statutes of Texas.
(1965 Code, sec. 15-5)
(a) 
No master plumber shall engage in, carry on or work at the business of plumbing in the city unless his name, address, telephone and state license number has been registered with the chief plumbing inspector.
(b) 
Vehicles used commercially in carrying on the business of plumbing by a master plumber shall have the firm name or the state license number affixed to both sides of the vehicle, so as to be in full view at all times and in letters not less than 2-1/2" high.
(1965 Code, sec. 15-45)