66 Williams Ave S, Renton, WA 98057

Office · Renton · Seattle-Bellevue metro, WA

One of 241 reachable office buildings in Renton. Larger than 21% of office buildings in Renton (median 7,578 SF), derived from assessor records.

Usable building area
2,849 SF, King County Assessor
Lot size
10,440 SF, King County Assessor
Year built
1979, King County Assessor
Stories
1, King County Assessor
Predominant use
Dental Clinic, King County Assessor
Assessed value
$997,200, per the King County Assessor (not a market appraisal)
Assessed value per usable SF
$350.02/SF, derived from assessor records
Usable area / lot
0.27, derived from assessor records
Vintage
1970s vintage
Zoning
CD, King County
County use code
Medical/Dental Office

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: $1.22M (estimated market value), with a likely range of $1.07M to $1.56M (half of recent verified sales in this segment landed inside that range). Based on 5 verified arm's-length comparable sales (through 2026-06-01). Not an appraisal. How this estimate works.

lower confidence: 2 comparable sales within 3 miles; nearest 2.2 mi. This property type carries wider measured error; treat the estimate as a starting point.

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: Office in Renton

median verified sale $283.97/SF over the trailing 24 months; 4 sales in the last 12 months and 9 in 24 (newest verified sale 2025-12); the middle 80% of recent sales traded at 0.96x to 1.35x their county assessed value, median 1.01x (9 sales with usable county values).

  • 2021: $294.01/SF median (5 sales)
  • 2022: $290.17/SF median (6 sales)
  • 2023: $272.49/SF median (7 sales)
  • 2024: $288.89/SF median (5 sales)
  • 2025: $274.56/SF median (4 sales)

This estimate sits at 1.22x county assessed value, the 78th percentile of those recent sale premiums.

Computed from 260 verified arm's-length sales in King County public records (9 in the trailing 24 months). Free public records. Not an appraisal.

Last sold: 2004-12-14 for $550,000 (recorded arm's-length sale).

Current ownership dates to 2004 (about 22 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$500K$1M$1.5M$2M201120142017202020232026$1.22M$997KCounty 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 $538,500 (2011) to $997,200 (2026), up 85% over 15 years, per county tax rolls. The 2026 roll splits $997,200 into $443,700 land and $553,500 improvements.

Taxes

Permit history

Source: King County permit records (newest first).