Cost to Build a House in Williamson County, Tennessee
Building a house in Williamson County, Tennessee costs about $165/sq ft in 2026 — roughly $290,400–$369,600 for a 2,000 sq ft mid-range home (construction only, land excluded). 1,286 single-family homes were permitted here in 2025, and the typical existing home is worth $945,249.
That is the Tennessee statewide rate: no public source measures construction cost county by county, so we don't invent a local premium. What does differ by county is measured below.
How much building happens in Williamson County
Single-family homes permitted each year, 2000–2025. 2025 is highlighted; the 2008–2011 crash years are darker.
Williamson County is building 34% fewer homes than it did before the crash, up from a low of 362 in 2009. A thinner builder market can mean fewer bids and longer waits for specialist trades.
U.S. Census Bureau Building Permits Survey, county annual files 2000–2025 (1-unit structures, total including imputation).
Build or buy in Williamson County?
Unusually, building a median-size new home in Williamson County costs about $491,971 less than buying the typical existing one. That gap is narrower than the Tennessee average of +34.3%, because existing homes here are pricier than in much of the state — which makes Williamson County one of the stronger cases for building in Tennessee.
The two sides are not the same product: the build is brand new at the median new-home size for the South, the existing home is typically older and smaller. Lot cost uses Tennessee's average land share, and local lot prices can be well above or below it. Full Tennessee build-vs-buy comparison
Existing home value: Zillow Home Value Index, single-family, middle tier (2026-08) — an index of typical value, not a median sale price. Land: FHFA Working Paper 19-01.
What builders declared on Williamson County permits (2025)
The average declared valuation was $821,136 per home, against our $330,000 estimate for a 2,000 sq ft mid-range build. The two measure different things: builders declare a valuation for permit-fee purposes, which routinely understates finished cost, and permits cover homes of every size and finish level. We show both because quoting only the flattering one would be dishonest.
Source: U.S. Census Bureau Building Permits Survey, 2025 annual data.
What building in Williamson County actually involves
Cost per square foot is one number. These are the conditions behind it.
How busy this market is
Williamson County ranks 9th of 94 counties in Tennessee for single-family permits issued in 2025, accounting for 4% of all the single-family homes permitted statewide that year.
That is an active market with a reasonable choice of builders.
U.S. Census Bureau Building Permits Survey, co2025a.txt (2025).
What land adds on top
Land averages 21.3% of finished property value in Tennessee, which is a markup of about 27% on construction cost. For the $330,000 build above, that implies roughly $89,100 for the lot.
This is a statewide figure. Lots inside Williamson County's built-up areas will run above it and rural parcels below, so treat it as an order of magnitude rather than a budget line.
FHFA Working Paper 19-01 land values.
Statewide factors
Trade wages, climate load, energy code and permit seasonality are set at state level, so they are the same for every Tennessee county. See them on the Tennessee page.
Cost by Home Size in Williamson County
| Home Size | Basic | Mid-Range | Premium |
|---|---|---|---|
| 500 sq ft | $60,997 | $82,500 | $112,340 |
| 1,000 sq ft | $121,995 | $165,000 | $224,681 |
| 1,500 sq ft | $182,992 | $247,500 | $337,021 |
| 2,000 sq ft | $243,989 | $330,000 | $449,362 |
| 2,500 sq ft | $304,987 | $412,500 | $561,702 |
| 3,000 sq ft | $365,984 | $495,000 | $674,043 |
| 4,000 sq ft | $487,979 | $660,000 | $898,723 |
| 5,000 sq ft | $609,973 | $825,000 | $1,123,404 |
Other Tennessee counties
Costs are estimates only and represent construction costs, excluding land, architect fees, permits, and landscaping. Land in Tennessee averages 21.3% of finished property value (FHFA), which adds roughly 27% on top of these construction figures.
Priced at the Tennessee state average, which is 0.88× the national average of $188/sq ft. Permit and home-value figures are specific to Williamson County.
Cost data: HouseBuildCalc Permit Cost Index (876,000+ building permits, 1,700+ ZIP codes), U.S. Census Bureau Survey of Construction, BLS Producer Price Index, NAHB Cost of Constructing a Home (published summaries). County permits: U.S. Census Bureau Building Permits Survey. Home values: Zillow Home Value Index. For planning purposes only.