621 20th Ave S, Seattle, WA 98144

Small-Bay Industrial · Seattle · Seattle-Bellevue metro, WA

One of 2,011 reachable small-bay industrial buildings in Seattle. Larger than 2% of small-bay industrial buildings in Seattle (median 10,000 SF), derived from assessor records.

Usable building area
1,155 SF, King County Assessor
Lot size
7,170 SF, King County Assessor
Year built
2010, King County Assessor
Stories
1, King County Assessor
Predominant use
Storage Building, King County Assessor
Assessed value
$665,000, per the King County Assessor (not a market appraisal)
Assessed value per usable SF
$575.76/SF, derived from assessor records
Usable area / lot
0.16, derived from assessor records
Vintage
2010s vintage
Zoning
RSL (M), King County
County use code
Warehouse

Nearby comparable buildings

Same building type, by distance. Assessor facts only; not an opinion of value.

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Sale history and market context

MakeMe Estimate: $988K (estimated market value), with a likely range of $811K to $1.12M (half of recent verified sales in this segment landed inside that range). Based on 7 verified arm's-length comparable sales (through 2026-06-01). Not an appraisal. How this estimate works.

lower confidence: 3 comparable sales within 3 miles; nearest 1.6 mi. This property type carries wider measured error; treat the estimate as a starting point. Comparable-sale caveat: the estimate is well above (more than double apart from) the $392.26/SF median of the shown comparable sales.

Comparable sales used as evidence

Recorded arm's-length sales of similar buildings nearby; nearer and more recent sales rank first. Buyer and seller names are withheld. Get this data via API.

Market context: Industrial in Seattle

median verified sale $313.30/SF over the trailing 24 months; 40 sales in the last 12 months and 81 in 24 (newest verified sale 2026-05); the middle 80% of recent sales traded at 0.66x to 1.59x their county assessed value, median 1.06x (80 sales with usable county values).

  • 2022: $360.01/SF median (39 sales)
  • 2023: $354.62/SF median (33 sales)
  • 2024: $329.79/SF median (32 sales)
  • 2025: $289.77/SF median (46 sales)
  • 2026 YTD: $307.69/SF median (11 sales)

This estimate sits at 1.49x county assessed value, the 86th percentile of those recent sale premiums.

Computed from 1,501 verified arm's-length sales in King County public records (81 in the trailing 24 months). Free public records. Not an appraisal.

Value over time

$0$500K$1M$1.5M201120142017202020232026$988K$665KCounty assessed valueMakeMe Estimate range

Dark line: county assessed value per King County tax rolls. Blue line: our estimate; dashed years are a modeled backcast built from recorded arm's-length sales in the building's segment, not estimates published at the time, and years without enough sales stay unmodeled. The shaded range is the model's measured error band; about half of verified sales in the segment land inside it. Not an appraisal. How this estimate works.

Land, site, and value history

Assessed value moved from $286,800 (2011) to $665,000 (2026), up 132% over 15 years, per county tax rolls. The 2026 roll splits $665,000 into $573,600 land and $91,400 improvements.

Taxes

Permit history

Source: King County permit records (newest first).