34 Pa. Code § 41.11 – Buildings occupied by tenants.

(a) The owner or lessor of any building occupied by more than one tenant shall keep the entire building well drained and the plumbing thereof in a clean and sanitary condition. The cellar, basement, yard, areaways, vacant rooms and spaces in all places used in common shall be kept in a sanitary and safe condition, and such common areas shall be properly lighted when buildings are in use.
(b) In the case of a building occupied by one tenant only, the responsibility for compliance with these rules shall rest with the owner or lessee.