71 Pa. Stat. § 510-19
The Department of Environmental Resources shall have the power, and its duty shall be, to investigate the sanitary condition of tenements, lodging and boarding houses, and, when the same are found to be a menace to those occupying the same, or employed therein, or to be overcrowded, to condemn the same, in such manner and subject to such limitations as may now or hereafter be provided by law, and to notify the owners or agents thereof, in writing, setting forth the unsanitary or overcrowded condition thereof, specifying the changes or alterations which shall be made thereto for the purpose of relieving such condition, and further specifying the time within such changes or alterations shall be completed or overcrowding relieved: Provided, That in making inspections as authorized by this section, the Department of Environmental Resources shall cooperate with the Department of Labor and Industry, for the purpose of avoiding any duplication of inspection or overlapping of functions.
For the purpose of making investigations authorized by this section, the officers and agents of the department shall, at all times, have the right of ingress into all tenement, lodging, and boarding houses.
71 P.S. § 510-19