In August 2025, the postal service announced a major change in their process affecting postmarks. Under the new rule, most letters will no longer be postmarked on the day the letter is received by a post office, but instead postmarked on the following business day when the letter is processed at a regional mail-processing facility.
What does this mean?
If a resident’s outgoing letter is subject to a postmark or delivery deadline, that piece of mail may need to be mailed one to three days earlier than what was previously expected.
What can I do?
Customers should still be able to request a same day postmark at a retail USPS window, but be familiar with how this procedural change affects mailing timelines. Wisconsin law has not changed, so payments required to meet a postmark deadline–like tax payments–are still subject to the postmark application rule.
For example:
Town of Star Prairie residents pay property taxes directly to the St. Croix County Treasurer.The first installment or full payment option is due on or before January 31. Payments are applied according to postmarks:
- Payments postmarked January are considered on time.
- Payments received by February 7 (grace period) are considered on time.
- Payments postmarked February and received after February 7 are late.