1100 S Massachusetts St, Seattle, WA 98134

Multifamily · Seattle · Seattle-Bellevue metro, WA

One of 6,731 reachable multifamily buildings in Seattle. Larger than 74% of multifamily buildings in Seattle (median 6,744 SF), derived from assessor records.

Usable building area
15,524 SF, King County Assessor
Lot size
16,830 SF, King County Assessor
Year built
1967, King County Assessor
Stories
3, King County Assessor
Predominant use
Apartment, King County Assessor
Units
23, King County Assessor
Assessed value
$4,879,000, per the King County Assessor (not a market appraisal)
Assessed value per usable SF
$314.29/SF, derived from assessor records
Usable area / lot
0.92, derived from assessor records
Vintage
1960s vintage
Zoning
LR3 (M), 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: $4.94M (estimated market value), with a likely range of $4.4M to $5.64M (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 $215K per unit at the midpoint (23 units).

moderate confidence: 4 comparable sales within 3 miles; nearest 1.1 mi.

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: Multifamily in Seattle

median verified sale $367.78/SF over the trailing 24 months; median $272,333 per unit; 157 sales in the last 12 months and 300 in 24 (newest verified sale 2026-05); the middle 80% of recent sales traded at 0.78x to 1.25x their county assessed value, median 1.00x (300 sales with usable county values).

  • 2022: $427.16/SF median (207 sales)
  • 2023: $403.69/SF median (125 sales)
  • 2024: $364.48/SF median (126 sales)
  • 2025: $376.55/SF median (168 sales)
  • 2026 YTD: $367.11/SF median (53 sales)

This estimate sits at 1.01x county assessed value, the 55th percentile of those recent sale premiums.

Computed from 6,951 verified arm's-length sales in King County public records (300 in the trailing 24 months). Free public records. Not an appraisal.

Last sold: 1999-05-27 for $1,594,925 (recorded arm's-length sale).

Current ownership dates to 1999 (about 27 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$4.94M$4.88MCounty 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 $1,388,000 (2011) to $4,879,000 (2026), up 252% over 15 years, per county tax rolls. The 2026 roll splits $4,879,000 into $2,187,900 land and $2,691,100 improvements.

Taxes

Permit history

Source: King County permit records (newest first).