Paying households under the every-other-year adjustment vs annual indexing, 2028-2050

What this dataset measures

Built to show, from official records, which kinds of income and households ESSB 6346 reaches beyond people who earn $1 million a year in wages: married couples sharing one deduction, retirees and heirs with one-time distributions, households whose capital gains push wages over the line, and future households as the threshold loses value. The amendment votes record which of these the Legislature considered and rejected.

Geography

Washington, United States

Unit of observation

Varies by table: federal individual income tax returns by AGI class and year; floor amendments; illustrative households; tax years

Update cadence

Irregular; update when IRS releases tax year 2023 state data or the law changes

Curator

FactHub Research Team

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

• build_reach.js Transformation manifest · text/javascript · 13.7 KB (14,012 bytes)

  Node.js script that builds every table and result from the IRS files, the roll-call XML and the threshold projection.

Saved analyses

Derived from

This dataset uses data from these FactHub dataset versions.

• Washington millionaires tax: who files over $1 million, how the threshold holds up, and how volatile the base is Version 2

Sources

1. Internal Revenue Service, Statistics of Income Primary data: Washington returns by AGI class (files 19in55cmcsv.csv to 22in55cmcsv.csv, e.g. https://www.irs.gov/pub/irs-soi/22in55cmcsv.csv)

   Retrieved October 21, 2026. Public domain (U.S. government work). Unrestricted

   Reliability: Government. Compiled by the IRS from filed individual income tax returns; state tables are published annually with a lag of about three years. Counts are rounded and amounts are in thousands of dollars.

2. Washington State Legislature web services Primary data: recorded floor votes on ESSB 6346 and its amendments

   Retrieved October 21, 2026. Public record of the Washington State Legislature. Public record

   Reliability: Government. The Legislature's official roll-call record, served as XML. Each record gives the motion (floor amendment number and sponsor), date and yea/nay counts.

3. Washington State Legislature Primary record: amendment list, floor numbers, outcomes, and each amendment's official EFFECT statement (texts at lawfilesext.leg.wa.gov/biennium/2025-26/Htm/Amendments/)

   Retrieved October 21, 2026. Public record of the Washington State Legislature. Public record

   Reliability: Government. Official bill page. EFFECT statements are written by nonpartisan legislative staff for each amendment.

4. Washington State Legislature Primary law used for the household calculations (Secs. 201, 205, 301, 302, 314, 316)

   Retrieved October 21, 2026. Public record of the Washington State Legislature. Public record

   Reliability: Government. Enacted session law, chapter 238, Laws of 2026. The Department of Revenue had issued no rules interpreting it as of October 21, 2026.

5. Washington State Legislature Capital gains tax rates, exemptions and deductions used in the household calculations (RCW 82.87.040, .050, .060)

   Retrieved October 21, 2026. Public record of the Washington State Legislature. Public record

   Reliability: Government. Codified statute. RCW 82.87.050 exempts all real estate and retirement-account assets from the capital gains tax.

6. Washington State Standard (via The Inlander) The Department of Revenue's estimate of 25,000 paying households, the starting point of the projection

   Retrieved October 15, 2026. News report; facts only used. Not redistributed; linked

   Reliability: News report. Nonprofit news outlet reporting the Department of Revenue's July 2026 revision of its payer estimate.

Limitations and reproducibility

Reproducible: build_reach.js regenerates every table from the public IRS SOI state files (19-22in55cmcsv.csv), the Washington Legislature's roll-call web service for ESSB 6346, and the threshold projection in FactHub dataset wa-millionaires-tax-reach (versions 1 and 2 hold the same projection). The household examples are deterministic arithmetic from the statute text.

• IRS figures count federal returns, not households, and federal AGI includes long-term capital gains that ESSB 6346 mostly removes from its base, so returns over $1 million of AGI are not the same group as payers of the tax.
• Tax year 2022 is the latest IRS state release used; the tax starts in tax year 2028.
• Return counts for an income type include any return reporting that item, however small; the IRS rounds state counts to the nearest 10.
• The household examples are illustrations of the statute as written, not estimates of how many such households exist. They hold the capital gains standard deduction at its 2025 value of $278,000 and assume no other deductions or credits.
• The payer projection holds real incomes and population constant and uses a Pareto approximation of the income distribution near $1 million, so it isolates the effect of the indexing rule; it is not a forecast. Real income growth would add payers under either indexing rule.
• No public data separates two-earner couples by each spouse's income, so the dataset cannot count couples who pay only because they share one deduction.