Summary. This page describes how Accessory Dwelling Units are defined according to typical housing codes.
The backyard studio pictured here, from DecoratedShed.com, is an example of an Accessory Dwelling Unit.
The text below is taken from the City Code of Iowa City, Title 17 (Building and Housing), Chapter 5 (Housing Code), Section 3 (Definitions).
ACCESSORY BUILDING/USE/STRUCTURE: A building, structure, or use which:
A. Is subordinate to the principal use of the property and contributes to the comfort, convenience or necessity of occupants, customers, or employees of the principal use; and
B. Is under the same ownership as the principal use or uses on the property; and
C. Does not include structures, structural features, or activities inconsistent with the uses to which they are accessory; and
D. Except for off street parking located on a separate lot as approved through a special exception, is located on the same lot as the principal use or uses to which it is accessory.