Section 12-401 - Qualifications for engaging in the business of providing plumbing, propane gas, and natural gas services(a) A person may engage in the business of providing plumbing services if: (1) the person is a master plumber or holder of a limited master plumber license; or(2) the person: (i) designates a master plumber or holder of a limited master plumber license who actively directs, controls, and is responsible for all plumbing services; and(ii) otherwise provides the plumbing services in accordance with this title.(b) A person may engage in the business of providing propane gas services if:(1) the person is the holder of a propane gas fitter certificate; or(2) the person: (i) designates a holder of a propane gas fitter certificate who actively directs, controls, and is responsible for all propane gas services; and(ii) otherwise provides the propane gas services in accordance with this title.(c) A person may engage in the business of providing natural gas services if: (1) the person is the holder of a master natural gas fitters license; or(2) the person:(i) designates a holder of a master natural gas fitters license who actively directs, controls, and is responsible for all natural gas services; and(ii) otherwise provides natural gas services in accordance with this title.