A new U.S. Postal Service rule that took effect Dec. 24 could affect residents who mail tax payments, returns and other time-sensitive documents that rely on a postmark to prove they were sent on time.
Under the rule, codified as Section 608.11 of the Postal Service’s Domestic Mail Manual, a postmark may reflect the date a piece of mail is first processed by an automated sorting facility — not necessarily the day it was dropped in a mailbox or handed over at a post office counter
For taxpayers and others facing firm deadlines, that distinction matters.
“Because most postmarks are applied at processing facilities, they do not necessarily represent either the place at which, or the date on which, the Postal Service first accepted possession of the mailpiece,” the USPS rule states. In some cases, the postmark date “may be later than the date that the mailpiece was first accepted.”
That means a letter placed in a blue collection box on a deadline day could receive a postmark dated the following day if it is not processed until then — potentially triggering late penalties from agencies that rely strictly on postmark dates, including the IRS and state and local tax offices.
The Postal Service says the rule does not change how mail is handled or postmarked, but instead clarifies how postmarks work and what information they actually convey. Postal officials note that automated postmarking has long occurred at regional processing centers, rather than at local post offices, and that the timing gap has become more common as transportation and processing schedules have evolved.
To avoid problems, USPS recommends that customers who need proof of the exact mailing date take extra steps.
Residents can request a free, hand-stamped “local” postmark at the retail counter of any post office. That manual postmark reflects the date the mailpiece is accepted at the counter and aligns with the date of mailing. Customers may also use Certified Mail, Registered Mail or purchase a Certificate of Mailing, all of which provide receipts showing when the Postal Service accepted the item.
Mailing items several days before a deadline or filing and paying electronically when possible are other ways to reduce risk.
The rule applies nationwide and is effective immediately. For more information, customers can contact USPS Senior Public Relations Representative Martha Johnson at martha.s.johnson@usps.gov or 202-268-2000, or visit usps.com for guidance on postmarks and proof of mailing.
