USPS policy change on postmarks may affect tax payments becoming delinquent, county treasurer warns

Oneida County Treasurer Tara Ostermann is encouraging residents who pay their property tax bills by mail to be aware of a recent U.S. Postal Service policy change that may affect when envelopes are postmarked.

“In August 2025, the Postal Service instituted a nationwide change as to when a postmark is affixed to incoming mail,” Ostermann explained in a email received by the River News. “Instead of postmarks being affixed when the item is first touched by the Postal Service, postmarks are now stamped at regional sorting centers.

That means your postmark could be several days after you put it in your mailbox.”

Ostermann cautioned those who plan to pay their property taxes by mail, to not wait until right before the deadline to put it in the mail.

“Many federal and state laws define timely payment based off the USPS postmark, meaning payments may be considered delinquent if they are mailed too close to the deadline — even if they were, in fact, placed in a mailbox before the deadline,” she explained. “To avoid this issue, we encourage property taxpayers to mail payments earlier to avoid becoming delinquent and accruing substantial late fees.”

Ostermann advised against taxpayers sending tax payments utilizing their personal bank’s online bill payment option, “as those payments are often done in bulk with many other customers’ payments and the envelope is not always postmarked, so there is a danger those could arrive late and become delinquent as well,” she said. 

Ostermann suggested another option could be to physically bring payment into the post office and request that they postmark the payment in front of you, or by sending it certified mail.