(1) Except as provided in subsection (7) of this section, a Washington return must be filed if the gross estate equals or exceeds the applicable exclusion amount.

(2) If a Washington return is required as provided in subsection (1) of this section:

(a) A person required to file a federal return must file with the department on or before the date the federal return is required to be filed, including any extension of time for filing under subsection (4) or (6) of this section, a Washington return for the tax due under this chapter.

(b) If no federal return is required to be filed, a taxpayer shall file with the department on or before the date a federal return would have been required to be filed, including any extension of time for filing under subsection (5) or (6) of this section, a Washington return for the tax due under this chapter.

(3) A Washington return delivered to the department by United States mail is considered to have been received by the department on the date of the United States postmark stamped on the cover in which the return is mailed, if the postmark date is within the time allowed for filing the Washington return, including extensions.

(4) In addition to the Washington return required to be filed in subsection (2) of this section, a person must file with the department on or before the date the federal return is or would have been required to be filed all supporting documentation for completed Washington return schedules, and, if a federal return has been filed, a copy of the federal return. If the person required to file the federal return has obtained an extension of time for filing the federal return, the person must file the Washington return within the same time period and in the same manner as provided for the federal return. A copy of the federal extension must be filed with the department on or before the date the Washington return is due, not including any extension of time for filing, or within thirty days of issuance, whichever is later.

(5) A person may obtain an extension of time for filing the Washington return as provided by rule of the department, if the person is required to file a Washington return under subsection (2) of this section, but is not required to file a federal return.

(6) During a state of emergency declared under RCW 43.06.010(12), the department, on its own motion or at the request of any taxpayer affected by the emergency, may extend the time for filing a Washington return under this section as the department deems proper.

(7)(a) A Washington return is not required to be filed for a decedent's estate if:

(i) The estate is not otherwise required to file an estate tax return to claim a specific election;

(ii) The decedent was survived by a spouse, and the decedent's qualifying family residence included in the decedent's gross estate passed from the decedent to the spouse, consistent with section 2056 of the internal revenue code; and

(iii) The value of the decedent's gross estate less the value of the decedent's interest in a qualifying family residence that is included in the value of the decedent's gross estate is less than the applicable exclusion amount.

(b) The following definitions apply to this subsection:

(i) "Principal place of residence" means a residence that, except as otherwise provided in this subsection (7)(b)(i), has been occupied by both the decedent and the decedent's spouse or domestic partner for more than six months of the 12 months immediately preceding the decedent's date of death. "Principal place of residence" also means a residence of the decedent and the decedent's spouse or domestic partner when, during the six-month period immediately preceding the decedent's date of death, the decedent, the decedent's spouse or domestic partner, or both the decedent and decedent's spouse or domestic partner, were confined to a hospital, nursing home, assisted living facility, adult family home, or home of a relative of the decedent or decedent's spouse or domestic partner for purposes of long-term care if the decedent and the decedent's spouse or domestic partner did not occupy any other residence for more than six months of the 12 months immediately preceding the decedent's date of death, and during the six-month period immediately preceding the decedent's date of death:

(A) The residence was temporarily unoccupied;

(B) The residence was occupied by either or both (I) the decedent's spouse or domestic partner, or (II) a person financially dependent on the decedent or the decedent's spouse or domestic partner for support; or

(C) The residence or portion of the residence was rented for the purposes of paying costs related to the care of the decedent or the decedent's spouse or domestic partner in a nursing home, hospital, assisted living facility, or adult family home.

(ii) "Qualifying family residence" means the principal place of residence of the marital community or domestic partnership at the decedent's date of death.

(iii) "Relative" has the same meaning as "member of the family" in RCW 83.100.046.

(iv) "Residence" means a single-family dwelling unit, whether such unit is separate or part of a multiunit dwelling, including the land on which such dwelling stands, regardless of whether ownership of the single-family dwelling unit and land on which the dwelling unit stands is vested in the same person. "Residence" includes:

(A) A single-family dwelling unit in a cooperative housing association, corporation, or partnership, when the decedent has an ownership share in such entity;

(B) A single-family dwelling unit situated upon lands the fee of which is vested in or held in trust by the United States or any of its instrumentalities, a federally recognized Indian tribe, a state of the United States or any of its political subdivisions, or a municipal corporation;

(C) A single-family dwelling unit consisting of a manufactured/mobile home or park model that has substantially lost its identity as a mobile unit by virtue of it being fixed in location and placed on a foundation with fixed pipe connections with sewer, water, or other utilities; and

(D) A single-family dwelling unit consisting of a floating home as defined in RCW  82.45.032.

Application—2024 c 82: "This act applies to decedents dying on or after January 1, 2025." [ 2024 c 82 s 2.]

Automatic expiration date and tax preference performance statement exemption—2024 c 82: "RCW 82.32.805 and 82.32.808 do not apply to this act." [ 2024 c 82 s 3.]

Tax preference performance statement exemption—Automatic expiration date exemption—2017 c 323: See note following RCW 82.04.040.

Part headings not law—2008 c 181: See note following RCW 43.06.220.

Finding—Intent—Application—Severability—Effective date—2005 c 516: See notes following RCW 83.100.040.