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4000 CR 123, ROUND ROCK, TX 78664

ROUND ROCK, 78664 — williamson County

3 bed2,094 sqftBuilt 1973

Property at a Glance

This home is estimated between $348,886 and $583,777, with a best estimate of $404,295. That places the property above the AM20SLXI - MH - SGT/SHU/SRR median of $233,506, in a neighborhood that appreciated 30.5% over the past year.

Estimated Value Range

$348,886 $583,777
Best Estimate
$404,295
WCAD Value
$1,022,061
Low Confidence

Based on 5 comparable properties(0 in the same subdivision)

There are 5 comparable properties within range, but none are in AM20SLXI - MH - SGT/SHU/SRR. The estimated range of $348,886 and $583,777 should be treated as a rough guide.

Comparable Properties (5)

4 bed 3 bath 2,018 sqft Built 1972
Raw Value $410,758
Adjusted Value $418,916

Adjusted +$10,478 for 76 sqft more living space and -$2,320 for being older. Net adjustment: +$8,158.

4 bed 2 bath 2,074 sqft Built 1977
Raw Value $571,739
Adjusted Value $583,777

Adjusted +$2,757 for 20 sqft more living space and +$9,281 for being newer. Net adjustment: +$12,038.

3 bed 4 bath 1,931 sqft Built 1985
Raw Value $352,911
Adjusted Value $403,226

Adjusted +$22,473 for 163 sqft more living space and +$27,842 for being newer. Net adjustment: +$50,315.

4 bed 3 bath 2,514 sqft Built 1979
Raw Value $392,871
Adjusted Value $348,886

Adjusted -$57,906 for 420 sqft less living space and +$13,921 for being newer. Net adjustment: -$43,985.

3 bed 2 bath 1,525 sqft Built 1981
Raw Value $307,284
Adjusted Value $404,295

Adjusted +$78,449 for 569 sqft more living space and +$18,562 for being newer. Net adjustment: +$97,011.

The Neighborhood

This home is valued 337.7% above the AM20SLXI - MH - SGT/SHU/SRR median of $233,506. With 471 homes in the subdivision, the property sits in the upper tier. The neighborhood appreciated 30.5% over the past year.

AM20SLXI - MH - SGT/SHU/SRR

outlier high
471 Properties
$233,506 Median Value
+30.5% YoY Change
2% Have Pool
3% Have Garage
This Home
$1,022,061
Median
$233,506

This home is +337.7% above the subdivision median.

Tax Analysis

The estimated annual property tax is $15,609 across all districts. With a homestead exemption claimed, that drops to $14,170 — saving $1,439 per year. That's $1,181 per month a buyer should budget. The assessed value increased +15.8% vs the subdivision average of +30.5%. This increase gives a protest opportunity score of 45 out of 100 — it may be worth challenging the appraisal.

Tax Districts

DistrictTypeRateAnnual Amount
Round Rock ISDSchool0.8931%$9,128
Williamson CountyCounty0.3694%$3,776
Austin Community Collegespecial0.1034%$1,057
Williamson County ESD #9 - Round RockESD0.0999%$1,021
Williamson County FM/RdCounty0.0443%$453
Upper Brushy Creek WCIDWater0.0170%$174
Williamson Central Appraisal Districtcad0.0000%$0
Total Annual Tax1.5272%$15,609
45 / 100

Moderate opportunity to protest.

Mortgage Context

At today's 30-year mortgage rate of 6.38%, a buyer financing $404,295 would pay approximately $2,524 per month (principal and interest only, excluding taxes and insurance).

Data sourced from Williamson County Appraisal District (WCAD), Texas Education Agency (TEA), and Federal Reserve Economic Data (FRED). Assessment values reflect the appraisal district's estimate, not market sale prices. Report generated 4/18/2026.

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