Residency rules, sticky taxes, and first-year steps (2026)
2026.1 Edition · Revised 2026-07-25 · DomusDay Research
The move changes the rate; the record decides whether it sticks. Utah keeps taxing until domicile actually changes, and its 183-day statutory test stays live while any Utah abode is maintained. Below: what follows leavers, and the Idaho steps that build the record.
A place of abode maintained in Idaho for the entire taxable year plus more than 270 aggregate days in the state makes a person a resident regardless of domicile. Presence for any part of a calendar day counts unless it was for a temporary or transitory purpose.
Source ↗An absence of at least 445 days across 15 months takes an individual out of resident status, with no more than 60 days in Idaho in any calendar year of the remaining absence. It is unavailable where an Idaho permanent home is occupied by a spouse or minor children more than 60 days in the year.
Source ↗Idaho allows a deduction of up to 60% of capital gain net income from the sale or exchange of qualifying Idaho property, computed on Form CG. Real property qualifies where held at least 12 months and sold on or after January 1, 2005.
Source ↗Idaho is the easy half. Utah decides whether the move counts, and it decides on evidence — the two tests below stay live until the record closes them out.
The full rules, the audit program, and every source: the complete Leaving Utah guide →
Top-bracket rates differ by 0.8%: Utah at 4.5%, Idaho at 5.3% — an illustration at the top marginal rate, not an effective-rate calculation.
The first weeks in Idaho matter more than they look: each step below produces a dated document, and dated documents are what answer a Utah examiner years later. Do them early and the record starts on your side of the timeline.
Idaho's residency definition for obtaining a driver's license, identification card, vehicle title, or registration is 30 days, changed from 90 days effective July 1, 2024.
Source ↗Vehicles are titled and registered in Idaho once the 30-day residency definition is met, through the Transportation Department's DMV and county offices.
Source ↗Registration is open to those who have lived in Idaho at least 30 days, with an accepted form of identification and proof of residence; Idaho also allows registration at the polls on election day.
Source ↗Idaho has no declaration-of-domicile instrument. The homeowner's exemption application, the registrations, and the filing pattern carry the record instead.
Source ↗The homeowner's exemption removes 50% of the value of an owner-occupied home and up to one acre of land from property tax, capped at $125,000 of value, and is applied for with the county assessor between January 1 and April 15.
Source ↗The Property Tax Reduction program is a separate income-limited benefit for qualifying homeowners, administered through the county assessor alongside the homeowner's exemption.
Source ↗An Idaho place of abode maintained for the entire taxable year, combined with more than 270 aggregate days in the state, makes an individual a resident regardless of domicile — the arrival mirror of the departure test.
Source ↗Idaho property acquired after the move starts its holding-period clock for the Form CG deduction — up to 60% of capital gain net income from qualifying Idaho property, with real property held at least 12 months.
Source ↗Medical and professional relationships established in Idaho create dated, located records on the arrival side of the residency pattern.
The arrival year is filed on Form 43 with the Form 39NR supplemental schedule; part-year residents may claim a prorated credit against tax due but not a refund of excess credit.
Source ↗Everything Idaho asks of a new resident, on its own plate: the Moving to Idaho guide →
Every rule on this page traces to a statute, regulation, or agency publication, listed in full on each state's own plate.
2026.1 Edition · Revised 2026-07-25 · DomusDay Research