53 Pa. Stat. § 4592
All and every person, or persons, with three years or more practical experience, engaged or engaging in the business or work of plumbing, house and building drainage in said cities, shall apply in writing to the said director of the department of public safety, department or board or bureau of health, for such certificate or license, and in boroughs, incorporated towns, and townships of the first class, such application shall be made to the Department of Health of this Commonwealth, or such department thereof, or department or board or bureau of health as the said department shall designate; and if, after proper examination made by the department or board or bureau of health of said cities, such person or persons so applying shall be found competent, the same shall be certified to the director of the department of public safety, department or board or bureau of health in the case of cities, and to the Department of Health of this Commonwealth in the case of boroughs and incorporated towns and townships of the first class, who shall thereupon issue a certificate or license to such person or persons, which shall, for the period of one calendar year or fractional part thereof next ensuing the date of such examination, entitle him or them to engage in or work at the business of plumbing, house and building drainage.
53 P.S. § 4592