Section 13-a - Penalties and payment to county treasurer(1) After the return of unpaid taxes by the receiver to the county treasurer, a penalty of five per centum of the amount of the unpaid tax shall be added by the county treasurer and charged upon each item thereof and collected when the same is paid, but said penalty need not be entered against each item where mechanical billing machines are used for rendition of tax bills, statements or receipts by the county treasurer.(2) The tax and five per cent penalty, plus interest on both such tax and penalty computed at the rate as provided in section thirteen-c of this tax act for each month, or part thereof, from the first day of February after the tax was levied, may be paid to the county treasurer at any time before the first day of September succeeding the date of the tax warrant.(3) Thereafter, payment of such unpaid taxes may be made at any time before sale of the land for unpaid taxes, upon payment of such tax, penalty, interest on both such tax and penalty computed at the rate as provided in section thirteen-c of this tax act for each month or part thereof from the first day of February, and the cost of advertising the land for sale for such unpaid taxes as apportioned by the county treasurer among the several parcels liable to be sold.N.Y. Suffolk County Tax Act § 13-a