- Assessment basis
- Idaho is a 100% assessment-ratio state: the assessor sets full market value with no ratio reduction. Tax = (assessed value − exemptions) × levy rate. The homeowner's exemption removes 50% of an owner-occupied home's value plus up to one acre, capped near $125,000 (2026), whichever is lesser.
- Reassessment cycle
- 44 ELECTED COUNTY ASSESSORS (Idaho Code 63-207) set MARKET VALUE of all property as of JANUARY 1 — Idaho is a 100% assessment-ratio state (full market value, no ratio reduction), with a physical reappraisal at least once every 5 YEARS. The Idaho STATE TAX COMMISSION oversees administration + centrally assesses OPERATING PROPERTY (utilities/railroads). TAX = (ASSESSED VALUE − EXEMPTIONS) × LEVY RATE.
- Reassessment trigger
- Values reset ANNUALLY from the market as of Jan 1. A newly-occupied mid-year home goes on a Subsequent/Occupancy roll (occupancy tax). Idaho has NO individual assessment cap; instead a 3% TAXING-DISTRICT BUDGET cap limits each district's property-tax budget growth (plus new construction + annexation).
- Personal & intangible property
- Business personal property is taxable + self-reported (declarations due March 15), with a per-taxpayer exemption per county. Operating property (utilities/railroads) is centrally assessed by the State Tax Commission.
- CRE forecasting note
- Watch the Jan 1 valuation date (Idaho's market ran hot then corrected 2020-2023, so a notice can lag/lead) and the tight appeal window (notices by the FIRST MONDAY IN JUNE, Board of Equalization by the FOURTH MONDAY IN JUNE). The real lever is the 3% district BUDGET cap — levy rates float to raise each capped budget, so a big value jump usually meets a lower levy, not a proportional tax increase. Business PP has a per-taxpayer exemption; operating property is state-assessed; the homeowner's exemption is residential-only.
- Residential note
- Idaho values your home at 100% of market as of January 1 each year, but you're taxed on the value AFTER the homeowner's exemption — which removes half your home's value plus up to one acre, up to about $125,000 — times your local levy. Apply once with the county assessor and check that it shows on your notice (claiming it on two homes now brings a penalty). Assessment notices arrive by the first Monday in June and you must appeal by the fourth Monday in June, so act fast. If you're 65+, widowed, disabled, or a qualifying veteran with limited income, apply for the Circuit Breaker (Property Tax Reduction) between January 1 and April 15 — it's worth $250-$1,500 and must be renewed yearly.
FILING REQUIRED RELIEF — Idaho's biggest breaks are claim-based and time-boxed. The HOMEOWNER'S EXEMPTION (50% of your home's value plus up to one acre, capped near $125,000) is applied for once with the county assessor — verify it appears on your notice, and note that since July 2024 claiming it on more than one property triggers repayment plus a matching penalty. The income-based CIRCUIT BREAKER (Property Tax Reduction, $250-$1,500) and the 100% disabled-veteran reduction must be filed EVERY year between January 1 and April 15. Miss the window and you lose the year's benefit.
APPEAL DEADLINE — Idaho's appeal window is unusually tight. Assessment notices are mailed by the FIRST MONDAY IN JUNE and you must appeal to the county BOARD OF EQUALIZATION by the FOURTH MONDAY IN JUNE — often only three to four weeks. From there it's the Idaho Board of Tax Appeals within 30 days, then District Court within 28 days. You cannot protest a prior year's value, and your evidence should be comparable sales from roughly the last year, near the January 1 valuation date.
REVENUE DRIVEN RATES — Idaho caps the BUDGET, not your assessment. Each taxing district's property-tax budget can grow only about 3% a year (plus allowances for new construction and annexation), and the levy rate is whatever it takes to raise that budget from the district's total taxable value — so when values jump, levy rates generally fall. Your bill is the sum of many overlapping district levies, and a big assessment increase does not translate one-for-one into higher taxes; watch the districts' budgets, not just your value.
RATIO CAUTION — Idaho assesses at 100% of market value, so your assessed value looks like the full price — but the number that gets taxed is AFTER the homeowner's exemption (which removes up to about $125,000 or half the home value) and any circuit-breaker relief, then multiplied by the levy. Because values reset every year as of January 1 and Idaho saw some of the nation's fastest appreciation then correction (2020-2023), an assessment can lag or lead the current market; read the taxable value and valuation date, not just the headline market value.
STATE ASSESSED — While the 44 county assessors value locally, the IDAHO STATE TAX COMMISSION centrally assesses OPERATING PROPERTY — utilities, railroads, and similar multi-county networks — and apportions that value to the counties, and it reviews and approves the county levy rates each fall. So a meaningful slice of the tax base (and the final levy check) sits at the state level rather than with your county assessor.
Primary sources: Idaho State Tax Commission property tax (tax.idaho.gov) + Idaho Code 63-207/63-205/63-602G/63-705/63-501A; Ada/Bannock/Idaho County/Latah/Canyon assessors (100% market value Jan 1, 5-yr physical reappraisal, homeowner's exemption 50%/one acre/$125k HPI-indexed, 3% district budget cap not assessment cap, circuit breaker $250-$1,500 apply Jan 1-Apr 15, notices first Monday June, BOE fourth Monday June, Board of Tax Appeals/District Court, occupancy tax); HB 292 (2023)/HB 304 (2025) credit; IACA roster (as of 2026-07-05). Confirm current rules and figures with the assessing authority before any use.