72 Pa. Stat. § 5880
In all cases where, heretofore or hereafter, real estate shall have been or shall be sold to a county at tax sale under one assessment, and the said real estate shall have been divided into parcels and the title of record to such parcels shall have become vested in different owners, the county commissioners, so long as title remains in the county, may permit the owner to redeem the parcel to which he, or they, shall hold title or have an interest of record, by having the said parcel assessed in the manner provided by law and by the payment of the proportion of all taxes with interest and costs due thereon, but less any penalties, as the assessment, so placed upon the parcel, shall bear to the assessment upon which the sale was had.
72 P.S. § 5880