134 E Main
Rexburg, ID 83440
(208) 359-6200 Option 3 Fax (208) 359-0856

Idaho Assessor’s Manual

The main duties of the County Assessor as defined by Idaho Code are as follows:

  • Identify taxable property and assign market value to each.
  • Act as an agent of the Idaho Transportation Department in titling and registration of motor vehicles.
Assessor Shawn Boice.

All properties are to be assessed at market value each year, with a physical inspection once every five years. Exemptions apply to certain properties with some being fully exempt from property taxation.

Three approaches to value are used in the assessment process:
  • Cost approach - Using current construction costs
  • Income approach - Where net income is capitalized
  • Market approach - By comparing sales of like properties
All three approaches to value are used, if applicable, to assign value to the various types of property in the county.

The Idaho State Tax Commission conducts an annual review of the assessed values by performing a ratio study. The ratio study measures:
  • Assessment level - Assessed value over sale price
  • Uniformity - Equity of assessments
  • Reliability - Confidence that assessed values are representative of the market.
Assessed values should reside between 90-110% of the market comparisons.

There are three main tax rolls each year –
  1. Main roll
  2. Subsequent roll
  3. Missed roll
These are used to equitably spread out the tax burden. Occupancy rolls are also compiled to add new construction values to the tax base.
After each roll is compiled, assessment notices are mailed to property owners. Appeals to the assessed values start with the assessor’s office to correct mistakes, next to the Board of Equalization (County Commissioners), then to the State Board of Tax Appeals or on to District Court to resolve value appeals.

Assessment notices are provided to property owners, and are mailed by the Assessor’s Office following each tax roll. The Assessor urges you to review assessment notices carefully, and contact the office if you have any questions. If you have factual information showing that your property was assessed incorrectly, you should call or come to the office to discuss it. The Assessor can make changes to values until the property rolls are completed and delivered to the county auditor. The taxpayer may still appeal the assessor’s value to the “Board of Equalization”; however, an appointment is required to meet with the board. Appointments can be made at the County Clerk’s office.


Property Assessment Methodologies
Idaho Property Tax Reduction: Circuit Breaker Program
Board of Equalization
Homeowners Exemption Application