22 Pa. Code § 131.47
A board of library directors of a local library or district center library may enter into a contract with the officers of a municipality to provide free library service to the residents and the taxpayers of that municipality or with another board of library directors to provide free service to the residents and taxpayers of all or a portion of the service area for which it is responsible. However, before any such contract is negotiated which would result in a library providing free service to residents of a library district other than the one in which it is situated, notice with opportunity to participate in the negotiation shall be given to the head librarians of the two district library centers involved. The contract shall be effective only upon approval of the State librarian.
22 Pa. Code § 131.47