53 Pa. Stat. § 16035
There shall be imposed and collected, upon all taxes registered as delinquent, in accordance with the provisions of this act, the following penalties, to wit: On the first day of February succeeding the registry of any tax as delinquent, a penalty of one per centum; and on the first day of each succeeding month of that year, up to and including the first day of August, an additional penalty of one per centum for each month together with lawful interest from the thirtieth day of December, of the year for which the said taxes were assessed; said penalties and costs to be paid by the delinquent taxpayer, and to be added on the amount of all such taxes, whether collected upon notice, or by levy, suit, lien or in the distribution of the proceeds of sheriff's or other judicial sales.
53 P.S. § 16035