53 Pa.C.S. § 8206: Effect of failure of timely action by department.

If the local government unit has submitted a filing to the department by certified mail, return receipt requested, or otherwise has an official receipt from the department, and the local government unit has not, within 20 days of the date of receipt of the filing by the department, received the certificate of approval or disapproval or notification of correctable error, the filing shall be deemed to have been approved for all purposes unless the local government unit has extended the time within which the department may act by written communication to the department or by failure to object to a written communication from the department requesting the extension. Extensions shall not exceed one additional period of 20 days.