Capital Gains Tax When Selling Your Home in Washington
Most WA home sellers owe zero capital gains tax. How the federal §121 exclusion works, why WA's capital gains tax exempts real estate, and the math.
Most Washington homeowners who sell their primary residence owe zero capital gains tax — federal or state. That’s not a loophole; it’s three rules stacking in your favor:
- The federal Section 121 exclusion shields up to $250,000 of gain ($500,000 for married couples filing jointly) on a primary residence.
- Washington has no state income tax, so there’s no state-level tax on the gain the way California or Oregon sellers face.
- Washington’s capital gains excise tax (the 7% tax on large long-term gains, enacted in 2021) explicitly exempts real estate. Your home sale doesn’t trigger it, full stop.
So the real question isn’t whether there’s a tax — it’s whether your gain clears the federal exclusion, and how to count your gain correctly. That’s where sellers leave money on the table, so let’s do the math properly. (Standard caveat, and we mean it: this article explains mechanics; a CPA applies them to your facts before you rely on any of it.)
Rule one: the §121 exclusion and the 2-of-5 test
You qualify for the full exclusion if, during the five years before the sale, you owned the home for at least two years and used it as your primary residence for at least two years. The two years don’t need to be continuous, the ownership and use periods don’t need to overlap, and you can use the exclusion repeatedly — just not more than once every two years.
| Filing status | Gain excluded |
|---|---|
| Single | Up to $250,000 |
| Married filing jointly | Up to $500,000 (both must meet the use test; only one needs the ownership test) |
Sell before hitting two years and you generally owe tax on the whole gain — unless you moved for qualifying reasons (work relocation beyond distance thresholds, health, certain unforeseen circumstances), which can earn a partial exclusion prorated by your time in the home. Partial-exclusion rules are exactly the “talk to a CPA” zone.
Rule two: your gain is smaller than you think
The gain is not sale price minus what you paid. It’s:
Amount realized (sale price − selling costs) − adjusted basis (purchase price + qualifying capital improvements + certain purchase costs)
Both adjustments work in your favor.
Selling costs reduce the amount realized: agent commissions, the REET excise tax, title and escrow charges, legal fees. On a Seattle-area sale these commonly total 5–7% of price — see the full seller cost stack — and every dollar of them shrinks your taxable gain.
Capital improvements raise your basis: the new roof, the remodeled kitchen, the added bathroom, the sewer line replacement, landscaping with permanence. Repairs and maintenance (repainting a room, fixing a leak) do not count. The IRS line is roughly betterment/restoration/adaptation vs. keeping it working — another spot where a CPA earns their fee.
Worked illustration: long-held Green Lake house, married couple
| Item | Amount |
|---|---|
| Purchase price (bought years ago) | $450,000 |
| Capital improvements over the years (roof, kitchen, sewer line) | $120,000 |
| Adjusted basis | $570,000 |
| Sale price (illustrative) | $1,400,000 |
| Selling costs (~6%: commissions, REET, title, escrow) | $84,000 |
| Amount realized | $1,316,000 |
| Gain | $746,000 |
| §121 exclusion (married filing jointly) | −$500,000 |
| Taxable gain | $246,000 |
Even on a home that tripled, the taxable slice is a quarter of the raw appreciation. Without the improvement records, though, this couple’s taxable gain would have been $120,000 higher — at a 15% federal rate plus possible net investment income tax, that’s roughly $20,000+ of real tax riding on a folder of receipts. Keep every improvement receipt for as long as you own the home. It’s the cheapest tax planning that exists.
What the taxable slice actually costs
Gain above the exclusion is a long-term capital gain (assuming over a year of ownership), taxed federally at 0%, 15%, or 20% depending on your income — most sellers with gains land at 15% — plus the 3.8% net investment income tax for higher earners. And again, for Washington: no state income tax, and the WA capital gains excise tax does not apply to real estate. The couple above owes roughly $37,000–$58,000 federal on their $246,000 slice depending on bracket and NIIT — on $746,000 of actual profit.
The situations that break the simple story
- It was a rental for a while. Two complications: depreciation you took (or could have taken) is “recaptured” at up to 25% and can’t be excluded under §121, and post-2008 rules treat certain rental years as nonqualified use that prorates the exclusion. If you’ve ever rented the home out, get professional help before you sell.
- Inherited homes get a stepped-up basis to the value at the owner’s death — often erasing decades of gain entirely. Different rules, different planning; don’t apply this article to an inheritance.
- Massive appreciation, single filer. Long-tenure Seattle owners can blow past $250,000 of gain easily. Timing of improvements documentation, filing status changes, and sale timing all matter — plan before listing, not at tax time.
- Second homes and investment property get no §121 exclusion at all (and investment property opens the separate world of 1031 exchanges).
What this means for your sale planning
Run the gain math before you list — it takes ten minutes with your purchase records:
- Dig out your purchase closing statement and improvement receipts.
- Estimate selling costs honestly (the seller cost guide gives the line items; our calculators help with the rest of the move’s math).
- Subtract basis and costs from your expected price; compare the gain to your exclusion.
- If you’re near or over the threshold — or any “breaking” situation above applies — book the CPA conversation now, while choices still exist.
Notice what the worked table quietly showed: at $1.4M, the selling costs ($84,000) were a third the size of the entire taxable gain — and unlike the tax, most of that number is negotiable, because most of it is agent compensation. Seeing what different agents actually charge before you sign is exactly what Manaky Homes is for: Greater Seattle agents publish their fees on a free, side-by-side marketplace — no paid placement, consumers pay nothing. It launches beyond the waitlist later in 2026; reserve your spot before you plan the sale.
