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USPS processes may delay postmarks on mail

U.S. Postal Service (USPS) recently issued a rule to improve public understanding of postmarks and their relationship to the date of mailing. Many people have long assumed their mail is postmarked the day they drop it in a mailbox or at a post office, but that’s not necessarily the case.

When postmarks are added to mail

Postmarks are generally applied by machines at the originating processing facilities. This can sometimes occur the same day that a piece of mail is deposited in the mail, but it oftentimes occurs one or more days later.  

This means your mail could be postmarked several days after you drop it in a mailbox. Because many state laws define timely payment based on the USPS postmark, payments, applications, or reports may be considered delinquent if they are mailed too close to a deadline — even if they were, in fact, placed in a mailbox before the deadline date.

Why the postmark date is important

According to Washington law, tax returns,  payments, and other time-sensitive correspondence mailed through the USPS are timely if they are postmarked on or before the due date. If a tax return or payment is postmarked after the due date, it is considered late and subject to penalties and interest.  This also applies to property tax applications.

What you can do

To avoid possible delinquency and late penalties, or rejections of petitions or applications as untimely:

  • File and pay online. Eliminate the worry about missing a due date because of a postmark date.
  • Mail early. Send time-sensitive mail several days before the deadline.
  • Go inside the USPS retail location. Take the mail inside the post office and choose one of these in-person options:
    • Request a manual postmark to ensure the date reflects when the USPS accepted your item.
    • Get a certificate of mailing. This works like a receipt, providing official proof of when you sent the item. (Keep your copy; USPS does not retain one.)
    • Send by registered or certified mail, as these methods provide mailing receipts and tracking.