First half real estate and mobile home taxes were due September 1st and must be paid by September 30th to avoid penalty.  On October 1st, a penalty of 1½% per month will be attached. In order to reduce wait times and provide the best service possible, the county treasurer encourages payments to be mailed to the Washington County Treasurer at PO Box 889, Washington, Iowa, 52353, placed in the drop box located by the west door of the courthouse, or paid online at www.iowatreasurers.org. Statement coupons must accompany payments.  Payments sent by mail must have a US Postal Service postmark date of September 30th  or earlier to avoid penalty.  Predated checks are not accepted as a substitute for the proper postmark. Contact the treasurer’s office at 319-653-7721 for more information or for help with alternate payment methods.