(a) General rule.--Notice of the view and hearing shall be served, within or without this Commonwealth, by any competent adult in the same manner as a civil action or by registered mail, return receipt requested, to the last known address of the condemnee and condemnor.

(b) Public posting.--If service cannot be made in the manner set forth in subsection (a), then service shall be made by posting a copy of the notice upon a public part of the property and by publication, at the cost of the condemnor, once in a newspaper of general circulation and once in the legal publication, if any, designated by rule or order of court for publication of legal notices, published in the county.

(c) Proof of service.--Proof of service and the manner of service shall be attached to the viewers' report.