7 Pa. Code § 137b.44
A county shall accept and process in a timely manner all complete and accurate applications for preferential assessment so that, if the application is accepted, preferential assessment is effective as of the tax year of each taxing body commencing in the calendar year immediately following the application deadline.
Example 1: An application for preferential assessment is filed on or before June 1, 2001. The county must review and process the application so that-if the application is approved-preferential assessment can take effect as of the commencement of the tax year of each taxing body commencing in 2002 (the calendar year immediately following the application deadline).
Example 2: An application for preferential assessment is filed at some point from June 2, 2001, through June 1, 2002. The county must review and process the application so that-if the application is approved-preferential assessment can take effect as of the commencement of the tax year of each taxing body commencing in 2003 (the calendar year immediately following the application deadline).
7 Pa. Code § 137b.44