New York State Real Property Tax Law Section 925, provides as follows: "Payment of taxes by mail, when enclosed in a postpaid wrapper (envelope) properly addressed to the appropriate collecting officer and deposited in a post office or official depository under the exclusive care and custody of the United States Post Office shall, upon deliver, be deemed to have been made to such officer on the date of the United States Postmark on such wrapper. The provisions of this section shall not apply in the case of postmarks not made by the United States Post Office. A postage meter postmark is not a postmark made by the United States Post Office and, therefore, is not within the provisions of Real Property Tax Law Section 925. Payments cannot be deemed timely because of a postage meter postmark date on an envelope containing a tax payment (Op. New York State Comptroller 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 Real Property Tax Law, and the interest must be added and collected. No Town official or employee can waive the interest (Op. New York State Comptroller 68-626.)