72 Pa. Stat. § 5020-515
In order to enable the board of school directors in each district of the third class, other than school districts of that class which are located wholly within the boundary lines of cities of the third class, and where such third-class school districts comprise the same territory as such city of the third class in which the same is so located, as aforesaid, and in each district of the fourth class in this Commonwealth, to assess and levy the necessary school taxes required by such district each year, the county commissioners, or board for the assessment and revision of taxes, in each county shall, on or before the first day of April in each year, at the expense of the county, furnish to each school district of the third class, other than school districts of that class which are located wholly within the boundary lines of cities of the third class, and where such third-class school districts comprise the same territory as such city of the third class in which the same is so located, as aforesaid, and to each district of the fourth class, therein, for its use, to be retained by it, a properly certified duplicate of the last adjusted valuation of all real estate, personal property, and residents or inhabitants made taxable for county purposes in such school districts, stating the name of each taxable, and the valuation, description, and kind of property, and a list of the residents or inhabitants assessed; all of which real estate, personal property, and residents or inhabitants are hereby made taxable for school purposes in each school district of the third and fourth class.
72 P.S. § 5020-515