If the first half of the current year real estate taxes are not paid by December 20, interest will start accruing December 21. You should receive a delinquent real estate tax reminder in February. If the mortgage company was to have paid these taxes, you must inform them that the Treasurer's office for the County did not receive the payment. If there are any questions, the mortgage company needs to call the County Treasurer's office at 785-537-6321.You or the mortgage company can pay the first half of the current year taxes with interest up until May 10. After May 10, if the first half of the real estate taxes has not been paid, the full amount of the current year tax plus interest will have to be paid. If the current year tax has not been paid by the first of August, there will be an additional fee of $16.00 for advertising. Riley County is required by Kansas State law (KSA 79-2303) to publish a list of unpaid real estate taxes. If taxes go unpaid by the first Tuesday after the first Monday in September, taxes will be put on the delinquent tax roll, and it becomes a lien on the real estate. If you want to pay delinquent years, Kansas State law (KSA 79-2401A) requires that the most delinquent year be paid first.