53 Pa. Stat. § 4599
The mayor of said cities is hereby authorized and required to appoint a practical plumber of at least ten years experience and not engaged or connected, directly or indirectly, with the plumbing business as plumbing inspector, whose duty it shall be to supervise, superintend, and inspect all plumbing, house and building drainage, in conformity with the provisions of this act. And the several cities are hereby authorized and required to make proper provision for the payment of the salary of the said plumbing inspector, as provided by law. Whenever the mayor of any city of the third class finds it impossible to secure as a plumbing inspector a qualified person who is not engaged in or connected with the plumbing business, he shall have the power to appoint a person who is engaged in or connected with such business, providing such person has the other qualifications herein prescribed. In such event, the mayor shall, as the occasion may arise, appoint a substitute inspector who shall supervise, superintend and inspect the work done by the regular inspector or by the firm with which he is connected in the course of their private business. Such substitute inspector shall be paid for such work reasonable compensation to be fixed by council.
In order to afford the opportunity for local administration and enforcement of this law, the council of any borough or incorporated town, or commissioners of a first class township, are hereby authorized, by appropriate municipal action providing therefor, to appoint a practical plumber not engaged or connected, directly or indirectly, with the plumbing business as plumbing inspector, whose duty it shall be to supervise, superintend and inspect all plumbing, house and building drainage, in conformity with the provisions of this act; and to make provisions for the payment of the salary of the said plumbing inspector whenever this is done by such municipality. When this is done, the matter shall be submitted to the Secretary of Health of this Commonwealth by application, setting forth the action taken, and the name of the person or persons selected as inspector, and his qualification. If the Secretary of Health is satisfied that the enforcement of the act can safely be left to the municipality under this action taken, he may commit the same to it. Should, in its administration after being thus committed, the local authorities fail in the proper administration of the law, then the Secretary of Health of this Commonwealth shall revoke such commitment upon reasonable notice and hearing, subject to this provision. In cases outside of cities, the Secretary of Health of this Commonwealth is authorized and required to appoint such number of practical plumbers who are not engaged or connected, directly or indirectly, with the plumbing business as plumbing inspectors for the Commonwealth of Pennsylvania, whose duty it shall be to supervise, superintend and inspect all plumbing, house and building drainage, under the provisions of this act, and to do any acts necessary for carrying this act into effect. He may, however, at his discretion and upon such terms as he may prescribe, appoint, permit or designate the plumbing inspector of any city or borough to perform these duties within a district or districts convenient. Should the Secretary of Health elect the latter, joint compensation between the several districts shall be effectuated.
53 P.S. § 4599