7 Pa. Code § 137b.24
A landowner seeking preferential assessment under the act shall include ineligible land on the application if the ineligible land is part of a larger contiguous tract of eligible land, and the use of the land which causes it to be ineligible exists at the time the application is filed. Although this ineligible land may not receive preferential assessment, the applicant shall specify the boundaries and acreage of the ineligible land, and may not expand the boundaries beyond those identified in the initial application. A landowner will not be required, as a condition of county acceptance or approval of the application, to survey or redeed the tract so as to exclude the ineligible land.
Example: A landowner owns a 100-acre tract of land, 90 acres of which is productive farmland and 10 acres of which is occupied by an auto salvage yard. If the landowner seeks preferential assessment of the 90 acres of farmland, the application shall describe the entire 100-acre tract. If preferential assessment is granted, it will apply to the 90 acres of farmland. The 10-acre tract would continue to be assigned its fair market value and assessed accordingly.
7 Pa. Code § 137b.24