53 Pa. Stat. § 16391
All the public plans of town plots, in the office of the clerk of the court of quarter sessions, and of the recorder of deeds, shall be deposited in the office of the board of surveyors, subject to the public inspection without charge; it shall be the duty of councils, under the supervision of the president of said board, to cause to be completed by the district surveyors, in sections, from time to time, a survey and plans of the city plot not already surveyed, according to the provisions of the laws under which the late district of Spring Garden was surveyed, one copy of which plans, when approved by the court, shall be filed in the office of said board, and the other in the office of the proper district surveyor, and in like manner, and with like approval existing plans may be revised and altered: Provided, That the plans made under existing contracts shall be approved by said board before being returned to court for confirmation; and that no ground shall be taken for public use under this act, without compensation, as provided, by law; the said board of surveyors, under the direction of the councils, shall have authority to alter the lines and regulate the grades of any street or streets, which may have been laid out upon any of the public plans or otherwise, but not opened, subject to the exception and the approval of the court of quarter sessions, as in the case where the plans are originally submitted for approval and confirmation.
53 P.S. § 16391