MILWAUKEE (CBS 58) -- Recent U.S. Postal Service operational changes mean some mail may not be postmarked until the day after it's dropped off, which could affect property tax payments sent close to deadlines.

The USPS has updated its transportation and mail processing network nationwide, and some items may not reach automated postmarking equipment until the following day. Under Wisconsin law, treasurer's offices use the USPS postmark to determine whether a mailed payment is on time.

Racine County issued an advisory about the changes, including the changes listed above, encouraging residents to mail payments earlier than usual or use alternative methods such as secure drop boxes, in-person payment or online portals. USPS also allows customers to request a hand-stamped postmark at the retail counter, which ensures the date of mailing is applied immediately.

According to the advisory, residents would be best served by checking with their municipal treasurer's office for specific payment options and deadlines.