It depends. NYS Real Property Tax Law 925 provides as follows: "Payment of taxes by mail, when enclosed in a postpaid wrapper (envelope) properly addressed to the appropriate collecting officer and is deposited in a post office or official depository under the exclusive care and custody of the US Post Office shall, upon delivery, be deemed to have been made to such officer on the date of the US Postmark on such wrapper. The provisions of this section shall not apply in the case of postmarks not made by the US Post Office. A postage meter postmark is not a postmark made by the US Post Office and, therefore, is not within in the provisions of Real Property Tax Law 925. Payments can not be deemed timely because of a postage meter postmark date on an envelope containing a tax payment (Op. New York State Comp.69-170). If taxes are not received until after the due date, they are not paid until after the due date unless they fall squarely within the provisions of section 925 of the Tax Law, and penalty must be added and collected. No Town official or employee can waive the penalty (Op. New York State Comp.68-626).