(1)    General rule. If payment is required by this chapter to be made by a taxpayer on or before a certain date, the payment is timely if it is mailed in a properly addressed envelope, postmarked before midnight of the prescribed due date for making the payment, with postage prepaid, and is received by the proper official, regardless of when it is received.

   (2)   Postal service delay. A payment which fails to satisfy the requirements of sub. (1) solely because of a delay or administrative error of the U.S. postal service shall be considered to be timely.

   (3)   County determination of postal service delay or error.

      (a)    In this subsection, “late payment” means a payment required under s. 74.11 or 74.12 which is not timely made under sub. (1).

      (b)    Any person required to pay interest or a penalty because of a late payment may, within 10 days of payment of interest or a penalty, but not later than December 1 of the year that the general property tax, special tax, special charge or special assessment was due, file a written request with the county treasurer requesting that the county board find that the late payment was timely under sub. (1) because the sole reason it was not timely was a delay or administrative error on the part of the U.S. postal service. The county board shall act on the request within 30 days after receipt of the request by the treasurer.

      (c)    The county board shall find that a late payment was timely under sub. (1) if it determines that the sole reason the payment was not timely was a delay or administrative error by the U.S. postal service. If it so finds, the county board shall direct that any interest or penalty paid because of the late payment be reimbursed to the taxpayer by the taxation district or county which collected the interest or penalty. A taxation district treasurer or county treasurer shall comply with a directive issued under this paragraph within 10 days.

      (d)    The county board may delegate the authority to make a determination under this subsection to any committee of the county board or committee or official of the county.

      (e)    This subsection does not affect the authority of a taxation district treasurer or county treasurer to consider payment timely under sub. (1) if the treasurer concludes that the payment fails to satisfy the requirements of sub. (1) solely due to a delay or administrative error by the U.S. postal service.

      (f)    This section does not apply to a city authorized to proceed under s. 74.87.