A surviving spouse in Washington generally owes no state estate tax on what they inherit from their husband, wife, or state registered domestic partner. Washington’s unlimited marital deduction lets any amount of property pass to the survivor free of state estate tax at the first death. The catch is that the tax is deferred rather than erased, and Washington’s rules differ from the federal ones in ways that can produce a large bill when the second spouse dies. Understanding the surviving spouse Washington state estate tax rules before the first death is where families save money; after, the options narrow considerably.
How the Marital Deduction Works
Washington’s estate tax code allows an unlimited transfer of assets to a surviving spouse without state estate tax. The deduction covers outright bequests, property passing through a will, and assets held in qualifying trusts. State registered domestic partners get the same treatment as married spouses.1Washington State Legislature. RCW 83.100.047 Marital Deduction, Qualified Domestic Trust – Election – State Registered Domestic Partner Entitled to Deduction
Because Washington is a community property state, only the decedent’s half of community assets is subject to tax in the first place. The full value of each community asset appears on the estate tax return, with one-half subtracted as the surviving spouse’s ownership share. Separate property is reported in full.2Washington Department of Revenue. Estate Tax FAQ Once the decedent’s half is identified, the marital deduction removes whatever portion of it passes to the surviving spouse.
The result at the first death is usually a zero tax bill. The house, the retirement accounts, the investment portfolio, and everything else the couple built together stays with the survivor.
The Tax Is Deferred, Not Eliminated
The marital deduction postpones estate tax rather than canceling it. When the surviving spouse later dies, everything remaining in that spouse’s estate is measured against Washington’s exemption threshold, and any excess is taxed.
For deaths occurring in 2026, the applicable exclusion amount is $3,076,000.3Washington Department of Revenue. Estate Tax Tables That figure changed in mid-2025. Washington held its exclusion at a flat $2,193,000 for years; starting July 1, 2025, the legislature raised it to $3,000,000 and added an annual inflation adjustment tied to the Seattle-area consumer price index. The exclusion recalculates each January based on the most recent October CPI, rounded to the nearest $1,000, with no downward adjustment if inflation is flat or negative.4Washington State Legislature. Washington Revised Code Chapter 83.100 Estate and Transfer Tax Act
If the surviving spouse dies with a taxable estate above the exclusion, graduated Washington rates apply. The top rate is now 35% on amounts above $9,000,000, up from the pre-2025 top rate of 20%.5Washington State Legislature. RCW 83.100.040 Estate Tax Imposed – Amount of Tax
Washington Does Not Recognize Portability
This is the trap that catches families who assume federal rules apply at the state level. Under federal law, when the first spouse dies, any unused portion of that spouse’s federal exemption can transfer to the survivor. Washington has no equivalent. Each estate gets only the exclusion amount in effect on the date of that person’s death.2Washington Department of Revenue. Estate Tax FAQ
Consider a couple with a combined estate of $5 million. If the first spouse leaves everything to the survivor through the marital deduction, the first spouse’s $3,076,000 exclusion goes unused, and Washington will not let the survivor inherit it. When the survivor later dies with $5 million, only one exclusion shelters the estate, and the excess is taxed.
The standard workaround is a bypass trust, sometimes called a credit shelter trust. The first spouse’s estate funds a trust up to the exclusion amount, which passes tax-free. The remainder goes to the surviving spouse under the marital deduction. The survivor can benefit from the trust during their lifetime, and at the second death, the trust assets are not part of the survivor’s taxable estate. Skipping this step is probably the single most expensive planning mistake Washington couples make at the state level.
The QTIP Election as a Planning Tool
A Qualified Terminable Interest Property trust lets an estate claim the marital deduction while controlling where the assets go after the surviving spouse dies. The trust must pay all of its income to the survivor for life, and no one else can receive distributions while the survivor is alive. This is common in blended families where one spouse wants to provide for the survivor but ensure the remainder eventually passes to children from a prior relationship.
Washington allows a state QTIP election that can differ from the federal one. A personal representative can elect a larger or smaller QTIP amount on the Washington return than on the federal return.6Washington State Register. WAC 458-57-115 Valuation of Property, Property Subject to Estate Tax, and How to Calculate the Tax That flexibility matters because Washington’s exemption is much lower than the federal one. When the surviving spouse later dies, only property for which a Washington QTIP election was made gets included in the survivor’s Washington taxable estate. Property elected only at the federal level is not added back for state purposes.1Washington State Legislature. RCW 83.100.047 Marital Deduction, Qualified Domestic Trust – Election – State Registered Domestic Partner Entitled to Deduction
Non-Citizen Surviving Spouses
The unlimited marital deduction is only available for outright bequests and QTIP trusts when the surviving spouse is a United States citizen. If the surviving spouse is not a citizen, the estate must use a Qualified Domestic Trust, known as a QDOT, to defer the tax.2Washington Department of Revenue. Estate Tax FAQ
A QDOT must have at least one trustee who is a U.S. citizen or a domestic corporation, and the trust document must give that trustee the right to withhold estate tax from any distribution of principal.7Office of the Law Revision Counsel. 26 USC 2056A Qualified Domestic Trust Distributions of income to the surviving spouse are generally not taxed, but any distribution of principal triggers estate tax as though it were part of the original decedent’s estate. Whatever remains when the surviving spouse dies is taxed the same way.
The QDOT election must be made on the estate tax return no later than one year after the return’s due date, including extensions. Missing that deadline means the marital deduction is lost entirely, and the full value of the non-citizen spouse’s inheritance becomes taxable at the first death. For mixed-citizenship couples, this is the most time-sensitive issue after a death.
Filing the Return Even When No Tax Is Owed
A surviving spouse who owes no tax still may need a Washington estate tax return filed. The return is what claims the marital deduction in the first place, and it must be filed within nine months of the date of death. The estate can request a six-month extension, but a copy of any federal extension must be submitted to the Department of Revenue by the original due date or within 30 days of the federal extension being granted, whichever is later.8Washington State Legislature. WAC 458-57-135
Even when no federal return is required, Washington demands a completed federal Form 706 as a supporting document, along with a certified death certificate.9Washington Department of Revenue. Estate Tax Filing Options and Forms All assets must be valued as of the date of death, with professional appraisals for real estate and account statements for financial holdings. The return requires detailed schedules identifying which assets pass to the surviving spouse; errors in the marital deduction claim are among the most common reasons the Department of Revenue requests additional information or adjusts a return.
After review, the department issues a closing letter confirming that the estate’s tax liability has been satisfied. That letter is needed to finalize the estate and clear any state claims against the property.
What to Do Before the First Death
If your combined estate is anywhere near the $3,076,000 exclusion, or likely to grow toward it, the decisions that determine whether a surviving spouse pays Washington estate tax are made while both spouses are alive. Leaving everything outright to the survivor uses the marital deduction but wastes the first spouse’s exclusion. A bypass trust, a state QTIP election, or a QDOT for a non-citizen spouse each preserve options that disappear once one spouse has died. An estate planning attorney familiar with Washington’s rules, not just federal ones, is the person to see.