Iowa Admin. Code r. 701—204.1(423) — Allowing use of the lowest tax rate within a database area and use of the tax rate for a five-digit area when a nine-digit zip code cannot be used

Any database maintained by the department that displays tax rates and tax jurisdictional boundaries based on either a five-digit or nine-digit zip code system shall, if an area encompassing one zip code has two or more rates of tax, provide to retailers a means of identifying and applying the lowest rate within the area for use in computing tax due. If a nine- digit zip code designation is not available for a street address or if a seller is unable to determine the nine- digit zip code designation of a purchaser after exercising due diligence to determine the designation, the seller may apply the lowest rate for the five-digit zip code area.