72 Pa. Stat. § 6111
If any tract of land hereafter sold for taxes shall not have bidden for it a sum equal to the whole amount of taxes and the costs then accrued, it shall be the duty of the commissioners of the proper county, or any of them, to bid off the same and a deed shall, thereupon, be made by the treasurer to the commissioners for the time being and their successors in office to and for the use of the proper county. And it shall be the duty of the commissioners to provide a book, wherein shall be entered the name of the person or persons as whose estate the same shall have been sold, the quantity of land or number of lot and number of tract, if any, the amount of the taxes and the costs it was sold for, and every such tract of land shall not thereafter, so long as the same shall remain the property of the county, be charged in the duplicate of the proper collector, but for five years next following such sale, if it shall so long remain unredeemed, the commissioners shall, in separate columns in the same book, charge every such tract of land with like county, school, road or other taxes as would have been chargeable against the said land had the same not been sold and purchased by the commissioners as aforesaid.
72 P.S. § 6111