53 Pa. Stat. § 4598
A re-examination will not be necessary for re-registration, unless the licensed master or journeyman plumber should have failed to make an application for re-registration at the specified time. The sum of one dollar shall be paid by master plumbers, firms, or corporations, and the sum of twenty-five cents by journeyman plumbers, for re-registration, which sum shall be paid into the State, city or municipal treasury, for their use. A register of all such applicants, and the license or certificates issued, shall be kept in said department, board or bureau of health, which said register shall be open to the inspection of all persons interested therein. Any person, firm, or corporation holding a license or certificate, granted by any city, borough, incorporated town or township of the first class of this Commonwealth, to engage in or work at the business of plumbing and drainage work, desiring to do plumbing or drainage work in any other city, borough, incorporated town or township of the first class than the one in which said license or certificate was granted, shall, without examination, be registered before entering upon such work: Provided, however, that such registration shall be restricted and limited to such plumbing and drainage work as he, they, or it shall have contracted for at the time of registry. On the completion of such contract or contracts the registration of such person, firm, or corporation shall be null and void, and no further permit shall be issued until he, or they, or it shall have first registered his or its name, or their names and address, as hereinbefore provided.
53 P.S. § 4598