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Williamson County

Williamson County Building Codes Department

In short

Williamson County Building Codes Department issues 3 permits we publish for Williamson County, last verified 2026-10-08. Each carries the fee as the agency publishes it, with a link to the schedule it was read from.

What this agency issues

Permits required, with issuing agency, fee, renewal term and the date each record was last verified against its source
Building Permit (unincorporated county)Williamson County Building Codes DepartmentPermit fee by total valuation: $1,000 and less = no fee, unless an inspection is required ($15 per inspection); $1,000–$50,000 = $15 for the first $1,000 + $5 per additional $1,000 or fraction; $50,000–$100,000 = $260 for the first $50,000 + $4 per additional $1,000; $100,000–$500,000 = $460 for the first $100,000 + $3 per additional $1,000; $500,001 and up = $1,660 for the first $500,000 + $2 per additional $1,000. Plan-checking fee (valuation over $1,000 with plans) = one-half of the building permit fee. Moving a building = $250. Demolition = $50 up to 100,000 cubic feet; $0.50 per 1,000 cubic feet at 100,000 cubic feet and over. $5 archives maintenance fee on every building permit. Re-inspection = $50 for the first failed inspection, $100 for the second, accumulating per failed inspection. Fees are doubled if work starts before the permit is obtained.per project2026-10-08
Plumbing and Mechanical Permits (unincorporated county)only if it applies to youWilliamson County Building Codes DepartmentPlumbing: $10 for issuing each permit; water $5; sewer $5; $2.50 per plumbing fixture, floor drain or trap (including water and drainage piping); $2.50 per water heater or vent. Mechanical: $10 permit fee + $10 for the first $1,000 of valuation + $2 per additional $1,000; repair, replacement or additions $5 + $2 per $1,000 of valuation.per project2026-10-08
Adequate Facilities Tax — New Non-Residential Floor Areaonly if it applies to youWilliamson County Building Codes Department$2.00 per gross square foot of new non-residential development, effective April 1, 2026 (it was $1.00 per gross square foot from January 1, 2026)one-time, per new building or addition2026-10-08

Fees shown as a range or formula are set that way by the issuing agency — we do not average them into a single number.

About each permit

Building Permit (unincorporated county)

As published in the 'Williamson County Schedule of Permit Fees' on Community Development letterhead, which the Building Codes Permits page links under 'Permit Costs' as 'the complete and current fees and requirements' (the sheet itself prints no adoption date), the permit fee is set from total valuation in five tiers, from no fee at $1,000 or less (unless an inspection is required, at $15 each) to $1,660 plus $2 per additional $1,000 above $500,000. The same schedule sets the plan-checking fee at one-half of the permit fee, a $250 moving fee, demolition at $50 up to 100,000 cubic feet or $0.50 per 1,000 cubic feet above that, and doubles the fees where work starts before the permit is obtained. The county's Justification of Development-Related Fees (dated 27 February 2026) lists the same upper tiers, a $5 archives maintenance fee charged on all building permits, and re-inspection fees of $50 for the first failed inspection and $100 for the second, accumulating. These are county permits for unincorporated Williamson County; each city issues its own building permits. Call Building Codes at (615) 790-5718.

Plumbing and Mechanical Permits (unincorporated county)

As published in the plumbing and mechanical fee schedules of the 'Williamson County Schedule of Permit Fees', which the Building Codes Permits page presents as 'the complete and current fees and requirements', a plumbing permit costs $10 to issue, plus $5 for water, $5 for sewer, $2.50 for each plumbing fixture, floor drain or trap and $2.50 for each water heater or vent. A mechanical permit costs a $10 permit fee plus $10 for the first $1,000 of valuation and $2 for each additional $1,000; repair, replacement or additions cost $5 plus $2 for each $1,000 of valuation. These apply to work in unincorporated Williamson County, such as a restaurant kitchen fit-out, a salon's added sinks, or new heating and cooling for a shop. Call Building Codes at (615) 790-5718.

Adequate Facilities Tax — New Non-Residential Floor Area

Per the official minutes of the Williamson County Board of County Commissioners for 10 November 2025, Resolution No. 11-25-39, as amended, raised the Adequate Facilities Tax on new non-residential development under Private Act No. 118 of 1987 and applied it to 'both the incorporated and unincorporated areas of Williamson County' at $1.00 per gross square foot from 1 January 2026, rising automatically on 1 April 2026 to $2.00 per gross square foot (the Commission amended the April figure from $1.50 to $2.00). The resolution's recitals record that the tax had previously been assessed only in the unincorporated areas at $0.34 per gross square foot. The tax therefore applies to a new restaurant, shop, clinic or other business building inside Brentwood, Fairview, Franklin, Nolensville, Spring Hill or Thompson's Station as well as in the county. The county's Schedule of Permit Fees lists 'Commercial $2.00 per square foot' and states that a separate check payable to the Williamson County Trustee is required. Call Building Codes at (615) 790-5718.

Contact

Jurisdiction
Williamson County
Phone
(615) 790-5718

Contact details are taken from the agency’s own site or its published fee schedule. Where we have not verified a phone number we leave it blank rather than guess.

Sources

Every fee and term above was read from one of these government pages on the date shown.

  1. Board of County Commissioners minutes, 10 November 2025 (Resolution No. 11-25-39, Adequate Facilities Tax)Williamson County Board of County Commissioners · primary source · retrieved 2026-10-08
  2. Building Codes — Permits (links the complete and current fees and requirements)Williamson County Building Codes Department · primary source · retrieved 2026-10-08
  3. Justification of Development-Related Fees — Building CodesWilliamson County, Tennessee · primary source · retrieved 2026-10-08
  4. Williamson County Schedule of Permit FeesWilliamson County Community Development · primary source · retrieved 2026-10-08

Other offices serving Williamson County

The full permit list for this jurisdiction

Industry permit lists that include this agency

Tennessee jurisdictions

Commercial Compliance Hub publishes information, not legal advice. Requirements change — confirm anything you rely on with the issuing agency before you file.