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. Montana keeps taxing until domicile actually changes, with no fixed day threshold to hide behind. Below: what follows leavers, and the Washington steps that build the record.
At Montana's top marginal rate (5.65%), every $100,000 of taxable income is $5,650 of state tax — an illustration at the top bracket, not an effective-rate calculation. Official rate tables are linked below.
Washington levies a 7% excise tax on an individual's long-term capital gains above an inflation-adjusted standard deduction ($278,000 for 2025), plus an additional 2.9% on annual gains over $1 million beginning tax year 2025 (ESSB 5813). Real estate and assets in certain retirement accounts are exempt.
Source ↗For deaths on or after July 1, 2025, the applicable exclusion is $3,000,000 ($3,076,000 for deaths January 1 through June 30, 2026, per the department's tables) and Table W rates top out at 35% on the taxable estate over $9 million.
Source ↗The Department of Revenue states that Washington has no individual income tax: wages, salaries, interest, and dividends are untaxed and there is no state income tax return. The capital gains excise tax and the estate tax are the two carve-outs worth noting.
Source ↗Washington is the easy half. Montana 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 Montana guide →
The headline delta: Montana taxes its top bracket at 5.65% while Washington has no personal income tax. At the top marginal rate — an illustration, not an effective-rate calculation — every $100,000 of taxable income is $5,650 of state tax that stops accruing once Montana residency actually ends. The rules above decide when that is; the day count and the domicile record decide whether it holds up.
The first weeks in Washington matter more than they look: each step below produces a dated document, and dated documents are what answer a Montana examiner years later. Do them early and the record starts on your side of the timeline.
New residents obtain a Washington driver license within 30 days of moving to the state; the license is also a prerequisite to registering vehicles.
Source ↗Vehicles are registered in Washington within 30 days of the move — the same 30-day window as the driver license.
Source ↗Voter registration is available online through VoteWA, by mail (arriving 8 days before an election), or in person at the county elections office until 8 p.m. on election day.
Source ↗The homestead exemption attaches automatically once the owner occupies the property as a principal residence (RCW 6.13.040) — no declaration is recorded for an occupied home. The exempt amount is the greater of $125,000 or the county's median single-family home sale price for the preceding year (RCW 6.13.030).
Source ↗Washington's mandatory liability minimums are $25,000 bodily injury per person, $50,000 per accident, and $10,000 property damage (25/50/10).
Source ↗Washington is a community property state: property acquired after marriage or registration of a domestic partnership by either spouse or partner is community property (RCW 26.16.030) — a title and estate-planning framework that begins applying with Washington domicile.
Source ↗Use tax on a private vehicle brought into Washington is waived when the vehicle was acquired and used in another state more than 90 days before the move and is licensed in Washington within 30 days; a vehicle purchased within 90 days of the move owes use tax at registration.
Source ↗Washington has no individual income tax and no state income tax return; the Department of Revenue's income tax page states the absence directly.
Source ↗Individuals with Washington-allocated long-term capital gains above the standard deduction ($278,000 for 2025) file a capital gains excise tax return electronically by the federal income tax deadline, with payment due April 15.
Source ↗Everything Washington asks of a new resident, on its own plate: the Moving to Washington 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