53 Pa. Stat. § 22771
The planning commission shall approve or disapprove a plat of a subdivision of land within thirty days after the submission thereof to it; otherwise such plat shall be deemed to have been approved and a certificate to that effect shall be issued by the commission on demand: Provided, however, That the applicant for the commission's approval may waive this requirement and consent to an extension of such period. Every plat approved by the commission shall, by virtue of such approval, be deemed to be an amendment of or addition to and become part of the municipal plan. Approval of a plat shall not be deemed to constitute or effect an acceptance by the public of any street or other open space shown upon the plat. The planning commission may from time to time recommend to council amendments of the zoning ordinance or map or additions thereto to conform to the commission's recommendations for the zoning regulation of the territory comprised within approved subdivisions.
53 P.S. § 22771