72 Pa. Stat. § 5341.7
The board shall issue annually, at such time as the board shall determine, its precepts to the real estate assessors assigned to the various real estate assessment districts, and the assessors shall, upon the receipt of such precepts, value each parcel of real property located within the districts to which they are assigned, and shall return such valuations to the board upon such date as the board shall provide. Such return shall be in such form as the board shall prescribe, but shall require the assessors to value separately the land and the improvements thereon in the case of each parcel of real property. The assessors shall also ascertain, and shall note in their returns, any division of any parcel, any change in the physical condition of the land or of the improvements located thereon, including the destruction or demolition of improvements and the erection of new improvements, and any change in the ownership thereof, occurring after the last preceding return was filed for such parcel, and such changes shall be noted on the records to be maintained by the board as provided in section six of this act.
72 P.S. § 5341.7