What if I waited until the last day and the post office was closed and I dropped my payment in the outside postal container on October 15; will I have to pay the penalty? Since the post office closes at 4:30, and you didn't get your payment postmarked on October 15, your postal mail will be postmarked October 16 and the 10% penalty will apply.
26-35-501. Time to pay
(1) A county collector shall assess a penalty of ten percent (10%) against all unpaid tax balances remaining after October 15 for every taxpayer other than a utility or carrier or after the prescribed dates listed in subsection (b) of this section for utilities and carriers.
(2) (A) A taxpayer paying in installments under subdivision (a)(2) of this section shall not be assessed a penalty until the taxes become due and remain unpaid after October 15. (B) However, if the last day for the payment of taxes on any installment is a Saturday, Sunday, or postal holiday, the last day to pay taxes without a penalty is the following business day.
(3) (A) A property tax balance payment is timely received under this subsection if mailed through the United States Postal Service and postmarked by October 15. (B) If October 15 is a Saturday, Sunday, or postal holiday, a property tax balance payment is timely received if mailed and postmarked through the United States Postal Service the following business day.