Apportionment of Operating Property

Apportionment is the process of assigning the value of operating property to the appropriate taxing district.


It’s done by calculating the value per mile of wire, pipe, or rail in Idaho and applying this rate per mile to each tax code area in which the wire, pipe, or rail is located. Apportionment for electric companies is done on a rate per wire mile for each county.

Some items, such as leased equipment and microwave facilities, are reported separately and assessed at their actual physical location.

For more information on apportionment, see Idaho Code section 63-405 and Property Tax Rules 405 and 413-417.


If an operating property owner disagrees with the appraised property value, the owner can meet with the appraiser to informally discuss the valuation and can also request a formal hearing before the Tax Commission. The owner must request a formal hearing before August 1. For more information on appeals, see Idaho Code sections 63-406 through 63-410 and Property Tax Rules 407 and 408.

Map orders

Every year Idaho counties submit tax code area changes to the Tax Commission’s Geographic Information Systems (GIS) section of the Property Tax Division. Digital copies of the maps for these tax code areas are available to the operating property owners, at no charge, on our website’s GIS and Property Tax page. You can also purchase CD or paper versions of these maps.

More Information

Assessments for operating property (also known as centrally assessed property) are developed by the Property Tax Division’s Operating Property Bureau. If you have questions, please contact that bureau or review these operating property forms, and guides.