In August of this year, the US Post Office announced a new rule that included without much fanfare a MAJOR change in when letters are postmarked. Under this new rule, most letters will no longer be postmarked on the day the letter is received by a post office but instead postmarked a day later when the letter is processed at a regional mail processing facility.
It is important that mailers understand the distinction between the date when the Postal Service first accepted possession of mailpiece and the date registered by machine-applied postmarks. If the mailpiece is destined for automated processing, a machine-applied postmark provides evidence of postal possession and shows both the location of the processing facility that applied the postmark and the date of the first automated processing operation performed on the mailpiece; but as noted above, it does not necessarily provide evidence of the precise date on which the Postal Service first accepted possession of the postmarked mailpiece. To be clear, however, any discrepancy between the date when the Postal Service first accepted possession and the date reflected on a postmark applied in a processing facility will be only one day in the vast majority of cases, and such discrepancy will generally exist only with respect to letter-and flat-shaped mailpieces that are both subject to RTO and cancelled at a processing facility. For mailpieces accepted within 50 miles of the servicing RPDC, the date on a postmark applied in a processing facility should generally continue to align with the date that the Postal Service first accepted possession of the mailpiece.
90 Fed. R. 38716, 38720 (12 Aug. 2025).
Save the Post Office has the details of this change at Say goodbye to the same-day postmark.
Mail sent Monday through Friday at a [non-regional processing facility post office] won’t be postmarked until the next day. Mail sent on a Saturday won’t be collected until Monday morning, and it won’t be scanned until Monday afternoon or evening, so the postmark will be two days after it was sent. If a piece is sent on a Saturday before a Monday holiday, it may not be collected, processed and postmarked until Tuesday — a gap of three days.
This change is a MAJOR departure from how the post office has traditionally handled letters. In the past, the postmark represents the date the post office has received the letter. And, much state and federal law is based on this practice.
Not anymore once this new regulation goes into effect (note: the timing of when this new postmark practice goes into effect is currently not specified).
The most obvious and widespread impact of this change will be on tax day, April 15th. Simply putting your tax forms in the mail on April 15th will now most likely mean that your tax forms will be late, since the Post Office will not post mark those tax forms until a day or two later (unless you live within 50 miles of the regional mail processing facility, which for Wisconsin is either Milwaukee or Minneapolis).
But, the impact will be more than just during tax day. Here is just a sample of various postmark requirements in state law.
- Wis. Stat. § 49.665(7)(a)2 — employer verification forms for public assistance due 30 days from postmark.
- Wis. Stat. § 200.35(5)(b) — sewage commission variances from zoning can be appealed within 90 days from postmark of that decision.
- Wis. Stat. § 8.35(2)(b) — vacancy of electoral candidate to be filled within four days of postmarked notice.
- Wis. Stat. § 32.05(5) and Wis. Stat. § 32.05(6) — court action challenging eminent domain and jurisdictional offer due 40 days and 20 days from date of postmark of certified letter.
- Wis. Stat. § 74.69(1) — state income tax payments timely if postmarked before midnight of the due date.
- Wis. Stat. § 74.87(7)(a) — property tax payments timely if postmarked by midnight of the due date (note: other provisions here allow for receipt within five days of the due date or administrative error by the postal service).
- Wis. Stat. § 108.09(2r) and Wis. Stat. § 108.10(1) — unemployment benefit appeals are timely if postmarked within 14 days of the date of the initial determination and employer tax appeals are timely if postmarked within 21 days of the date of the tax determination.
So, Wisconsin law generally presumes that all mail is postmarked when mailed (i.e., picked up that day by a letter carrier).
But, under this proposed postmark practice, any letters mailed outside of a fifty mile radius from a regional processing facility will NO LONGER BE POSTMARKED when received by the post office but will instead be postmarked a day or two later (or more) when the letter is processed at a regional mail facility.
In Wisconsin, the only post offices within that 50 mile radius of the regional processing facility in Milwaukee are marked in yellow and blue in the following map:
As evident here, most of the state is outside of this 50-mile radius. So, most mail in the state will soon be postmarked a day or more after being received by the post office. The only alternative, as explained by Save the Post Office in its description of the new postmark practice, is:
The [postmark] is still available at post offices, but a customer must request it at the retail window when the mailpiece is tendered for mailing. This, along with mailing the piece certified, is about the only way to ensure that the date on the postmark aligns with the date on which the Postal Service first accepted possession of the mailpiece.
That is, to have a letter postmarked when mailed, a certified letter is needed or a specific request to a post office clerk to postmark the letter immediately. Otherwise, the letter will be postmarked a day or more after the post office has actually received the letter.
Note: I have notified the Department and the Commission of this major change in postmark practice, but have not received a response from either.
Until laws are changed to reflect this new postmark practice, appeal deadlines have been shrunk by one to three days. Watch out.