15237 21st Ave SW, Burien, WA 98166

Multifamily · Burien · Seattle-Bellevue metro, WA

One of 281 reachable multifamily buildings in Burien. Larger than 72% of multifamily buildings in Burien (median 10,533 SF), derived from assessor records.

Usable building area
20,976 SF, King County Assessor
County gross area
32,267 SF, King County Assessor
Excluded area
11,291 SF outside primary usable area
Lot size
39,375 SF, King County Assessor
Year built
1983, King County Assessor
Stories
3, King County Assessor
Predominant use
Apartment, King County Assessor
Units
38, King County Assessor
Assessed value
$6,005,000, per the King County Assessor (not a market appraisal)
Assessed value per usable SF
$286.28/SF, derived from assessor records
Usable area / lot
0.53, derived from assessor records
Vintage
1980s vintage
Zoning
MU-1, King County
County use code
Apartment

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: $5.34M (estimated market value), with a likely range of $4.75M to $6.1M (half of recent verified sales in this segment landed inside that range). Based on 8 verified arm's-length comparable sales (through 2026-06-01). Not an appraisal. How this estimate works. About $141K per unit at the midpoint (38 units).

moderate confidence: 8 comparable sales within 3 miles; nearest 0.8 mi.

Comparable sales used as evidence

Recorded arm's-length sales of similar buildings nearby; nearer and more recent sales rank first. The strongest 5 of 8 nearby verified sales are shown. Buyer and seller names are withheld. Get this data via API.

Market context: Multifamily in Burien

median verified sale $241.87/SF over the trailing 24 months; median $185,567 per unit; 13 sales in the last 12 months and 19 in 24 (newest verified sale 2026-05); the middle 80% of recent sales traded at 0.73x to 1.32x their county assessed value, median 0.97x (19 sales with usable county values).

  • 2022: $251.87/SF median (11 sales)
  • 2023: $244.24/SF median (8 sales)
  • 2024: $184.24/SF median (5 sales)
  • 2025: $241.87/SF median (10 sales)
  • 2026 YTD: $288.83/SF median (6 sales)

This estimate sits at 0.89x county assessed value, the 37th percentile of those recent sale premiums.

Computed from 369 verified arm's-length sales in King County public records (19 in the trailing 24 months). Free public records. Not an appraisal.

Last sold: 1982-08-16 for $165,000 (recorded arm's-length sale).

Current ownership dates to 1982 (about 44 years) per recorded transfers.

Source: King County recorded sales extract; buyer and seller shown only when a company or organization. Individual names are withheld.

Value over time

$0$2M$4M$6M$8M201120142017202020232026$5.34M$6MCounty 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. Diamonds: recorded arm's-length sales. Not an appraisal. How this estimate works.

Land, site, and value history

Assessed value moved from $2,311,000 (2011) to $6,005,000 (2026), up 160% over 15 years, per county tax rolls. The 2026 roll splits $6,005,000 into $718,500 land and $5,286,500 improvements.

Taxes