Bolthole Index

Williamson County, Tennessee

Building permits, zoning and land rules in Williamson County, Tennessee

58Index Score / 100
#88 of 95 in Tennessee

Unincorporated Williamson County, Tennessee requires county building permits before construction, conversion or structural alteration of buildings1. County zoning applies outside municipalities, while the Department of Sewage Disposal Management administers individual onsite septic systems throughout Williamson County23. Confirm the zoning district and wastewater feasibility before settling on a house plan45.

At a glance

Building permit
Required before construction, conversion or structural alteration in unincorporated areas1
Zoning
Applies throughout unincorporated Williamson County2
Septic
County construction permit, layout inspection and final inspection required567
RV living
Temporary shelter may be permitted during home construction or after a disaster; general long-term use is unconfirmed89
Tiny home
Must be classified as an allowed dwelling use and meet district, code and wastewater rules1011
Owner-builder
Available for an owner's own residence, subject to state conditions and local permits12
Minimum lot size
Varies by district, structure type and subdivision type13

Who to call

Building permits

Williamson County Building Codes Department

Residential building permits and inspections under the adopted International Building Code for unincorporated Williamson County

(615) 790-5718

Info.buildingcodes@williamsoncounty-tn.gov

1320 West Main Street, Suite 400, Franklin, TN 37064

Planning & zoning

Williamson County Planning Department

Zoning administration, zoning inquiries and land-use guidance for unincorporated Williamson County

(615) 790-5725

Info.planning@williamsoncounty-tn.gov

1320 West Main Street, Suite 400, Franklin, TN 37064

Septic permits

Williamson County Department of Sewage Disposal Management

Individual onsite septic-system permitting and enforcement in Williamson County

(615) 790-5751

Info.sewagedisposal@williamsoncounty-tn.gov

1320 West Main Street, Suite 411, Franklin, TN 37064

Contact details are copied from each office’s official page and were checked against it on October 12, 2026.

Off-grid gear

Going off-grid in Williamson County means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Williamson County, Tennessee?

Unincorporated Williamson County requires a building permit before locating, erecting, constructing, reconstructing, extending, converting or structurally altering a building or structure, unless an applicable exemption applies; work cannot begin before issuance1. Necessary water-supply, sewer or septic, storm-water and driveway approvals, plus an approved Zoning Certificate, must precede the building permit1. Williamson County uses the 2021 building, residential, plumbing and mechanical codes, excluding the residential automatic-sprinkler provision and electrical chapters, and the 2018 energy code with 2009 tables; electrical permits for unincorporated projects come through Tennessee1415. A qualifying owner may build one residence for personal use every two years, but not for sale, lease or rent; the contractor-license exemption does not waive local building permits, and anyone hired whose portion costs $25,000 or more still needs the applicable contractor license12.

Who issues building permits in Williamson County, Tennessee?

The Williamson County Building Codes Department handles county building-permit applications; reach Building Codes at (615) 790-5718, Info.buildingcodes@williamsoncounty-tn.gov, or 1320 West Main Street, Suite 400, Franklin, TN 370641617. Apply online through the county Electronic Plan Review System and consult the published fee-and-requirements document; building permits and privilege taxes require separate checks1618. Construction inspections include footings, foundation, slab, applicable slab plumbing, framing, mechanical and plumbing; each re-inspection costs $501920. Electrical permits for unincorporated projects are available separately through Tennessee’s CORE system17. The Town of Nolensville issues its own building permits; the Town of Smyrna, listed as mainly in Rutherford County and reaching into Williamson County, also issues its own building permits2122. For a municipal parcel in Williamson County, ask the county Department of Sewage Disposal Management to confirm septic jurisdiction before applying5.

Does Williamson County, Tennessee have zoning?

Williamson County zoning governs development in unincorporated areas; Franklin, Brentwood, the Town of Nolensville and the Town of Smyrna, mainly in Rutherford County and reaching into Williamson County, set their own zoning within municipal limits223242526. County regulations require septic construction permits throughout Williamson County; ask the Department of Sewage Disposal Management to confirm the septic authority for a municipal address63. The county’s online zoning ordinance and map are reference materials; the print ordinance and subsequent amendments control discrepancies4. Minimum lot area in the A district is 15 acres; RP-5 and RD-5 residential lots in traditional subdivisions require 5 acres13. MGA-5 residential standards require 5 acres and setbacks of 100 feet front, 20 feet side and 60 feet rear2728. Setbacks can depend on recorded plats and lot history, while height limits vary by district and use293031. Conservation subdivisions require Planning Commission concept-plan approval followed by preliminary and final plats32. Agricultural subdivisions require a preapplication conference and final plat; created lots must be at least 1 acre and overall density cannot exceed 1 lot per 5 acres33.

How do septic permits work in Williamson County, Tennessee?

Williamson County's Department of Sewage Disposal Management administers individual onsite septic systems and designates the appropriate system type for each property35. A valid construction permit is required before a conventional or alternative septic system is built, altered, extended, modified or repaired6. Every installation needs a layout inspection before construction and a final inspection, with additional inspections possible for the soil, trenches or system type7. Reach the department at (615) 790-5751, Info.sewagedisposal@williamsoncounty-tn.gov, or 1320 West Main Street, Suite 411, Franklin, TN 3706434. Only about 14% of county soils rate as free of severe limitations for a conventional drain field, so establish wastewater feasibility before fixing the house location35. Pit privies and composting toilets require Board of Health approval and a recorded restriction or agreement; a pit privy cannot be the primary disposal method for a building with running water, and privies are limited to parcels over 10.01 acres and parcels without habitable or permanent structures36.

Can you live in an RV or tiny home in Williamson County, Tennessee?

Williamson County may issue a Temporary Use Permit for an RV or travel trailer during primary-home construction, after the home’s building permit is issued; approved water and sewage disposal and district setbacks are required8. The construction shelter permit lasts one year, with one six-month renewal possible only after permanent construction begins8. Temporary RV shelter may also be permitted after fire or natural disaster makes a single-family dwelling uninhabitable9. We could not confirm general long-term RV living or private-land camping; ask Williamson County Planning about the parcel and intended duration37. A primary tiny home must qualify as an allowed dwelling use and meet district, building-code and wastewater rules; the dwelling-unit definition excludes RVs1011. An accessory dwelling needs an eligible district and Minor Site Plan review38. Williamson County allows only one accessory dwelling per parcel, limited to 750 square feet or 25% of the principal dwelling, whichever is greater, but never more than 75% of the principal dwelling; a deed restriction must be recorded before zoning and building approval39. An accessory tiny home classified as a mobile home is allowed only in districts that allow mobile homes39.

What are the steps to build a home in Williamson County?

  1. Ask Planning to confirm the parcel's jurisdiction, zoning district, permitted dwelling type, setbacks and any subdivision review40414237.
  2. Establish wastewater feasibility and obtain the county septic construction permit before system work begins56.
  3. Resolve access: lots generally must abut a public road, while access easements and easement-dependent subdivisions have specific standards43.
  4. Apply for a Zoning Certificate before development on property containing a special flood-hazard area44.
  5. Submit building and related applications through the Electronic Plan Review System and consult the current county fee materials1618.
  6. Arrange county building inspections and separate state electrical permitting1917.
  7. Complete septic inspections; flood-hazard projects also require final elevation documentation before a Certificate of Compliance or Occupancy can issue745.

What should you check before buying land in Williamson County?

Before buying undeveloped land in Williamson County, have Planning verify the zoning district, allowed dwelling type, lot size, setbacks, building height and subdivision history411330464237. Check wastewater capacity early because only about 14% of county soils rate as free of severe limitations for a conventional drain field35. Confirm legal access because county rules generally require public-road frontage unless an access-easement exception applies43. A driveway on state highway right-of-way requires a TDOT entrance permit47. Special flood-hazard areas carry preservation, engineering and development limits beyond ordinary zoning48. We could not confirm a countywide private-well permit rule or general utility-connection rule, so ask Planning and the prospective service provider before closing37.

Watch-outs

  • Temporary RV shelter during construction requires the primary home's building permit first, plus a temporary-use permit, approved water and sewage disposal, and compliant setbacks8.
  • A tiny home is not exempt from ordinary dwelling rules; its zoning classification, building-code compliance and wastewater approval still control10.
  • Agricultural-subdivision approval requires a preapplication conference and final plat; do not treat that process as permission to build a house or barn without consulting Building Codes33117.

Sources

  1. Williamson County, Tennessee Zoning Ordinance, quoted and re-checked
  2. Zoning | Williamson County, TN, quoted and re-checked
  3. Sewage Disposal, quoted and re-checked
  4. Zoning, quoted and re-checked
  5. Sewage Disposal, quoted and re-checked
  6. Regulations Governing On-Site Sewage Disposal Systems, quoted and re-checked
  7. Regulations Governing On-Site Sewage Disposal Systems, quoted and re-checked
  8. Williamson County Zoning Ordinance, quoted and re-checked
  9. Williamson County Zoning Ordinance, quoted and re-checked
  10. Williamson County Zoning Ordinance, quoted and re-checked
  11. Williamson County Zoning Ordinance, quoted and re-checked
  12. Residential Permit FAQs, quoted and re-checked
  13. Williamson County Zoning Ordinance, quoted and re-checked
  14. Adopted Codes, quoted and re-checked
  15. Adopted Codes | Williamson County, TN, quoted and re-checked
  16. Building Permits | Williamson County, TN, quoted and re-checked
  17. Williamson County Building Codes Department (williamsoncounty-tn.gov)
  18. Building Permits | Williamson County, TN, quoted and re-checked
  19. Inspections | Williamson County, TN, quoted and re-checked
  20. Inspections, quoted and re-checked
  21. Town of Nolensville: Building in Nolensville (Williamson County), quoted and re-checked
  22. Town of Smyrna: Permits (Williamson County), quoted and re-checked
  23. Franklin: Franklin Zoning Ordinance 2024 (Williamson County), quoted and re-checked
  24. Brentwood: Sec. 78-144. Technical standards (Williamson County), quoted and re-checked
  25. Town of Nolensville: Nolensville Zoning Ordinance, § 4.3.9 Uses (Williamson County), quoted and re-checked
  26. Town of Smyrna: Town of Smyrna Municipal Zoning Ordinance (Williamson County), quoted and re-checked
  27. Williamson County Zoning Ordinance, quoted and re-checked
  28. Williamson County Zoning Ordinance, quoted and re-checked
  29. Williamson County Zoning Ordinance, quoted and re-checked
  30. Williamson County Zoning Ordinance, quoted and re-checked
  31. Williamson County Zoning Ordinance, quoted and re-checked
  32. Williamson County Zoning Ordinance, quoted and re-checked
  33. Williamson County Subdivision Regulations, quoted and re-checked
  34. Williamson County Department of Sewage Disposal Management (williamsoncounty-tn.gov)
  35. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  36. Regulations Governing On-Site Sewage Disposal Systems, quoted and re-checked
  37. Williamson County Planning Department (williamsoncounty-tn.gov)
  38. Williamson County Zoning Ordinance, quoted and re-checked
  39. Williamson County Zoning Ordinance, quoted and re-checked
  40. Zoning, quoted and re-checked
  41. Zoning | Williamson County, TN, quoted and re-checked
  42. Williamson County Subdivision Regulations, quoted and re-checked
  43. Williamson County Zoning Ordinance, quoted and re-checked
  44. Williamson County Zoning Ordinance, quoted and re-checked
  45. williamsoncounty-tn.gov, quoted and re-checked
  46. Williamson County Zoning Ordinance, quoted and re-checked
  47. Highway Entrance Permits (Tennessee statewide rule), quoted and re-checked
  48. Williamson County Zoning Ordinance, quoted and re-checked

Written October 12, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

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Compared with neighboring counties

Like all 6 of its neighbors, Williamson County requires a building permit for a home.

RuleWilliamson CountyMaury CountyDavidson CountyCheatham CountyDickson CountyRutherford CountyMarshall County
Building permitRequiredRequiredRequiredRequiredRequiredRequiredRequired
County zoningYesYesYesYesYesYesYes
Septic permitsWilliamson CountyTDECMetro Public Health Dept.TDECTDECTDECTDEC

County locator

Williamson County in Tennessee

58
County map
Williamson County highlighted among the Tennessee counties · colored by Index score

How Williamson County scores

Seclusion24100% ev.
Self-Sufficiency74100% ev.
Admin Boringness46100% ev.
Durability72100% ev.
Property Autonomy71100% ev.
Carry Cost61100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$931kTypical home
0.4%Property tax
$7,148Land / acre
53.5"Annual rain
3.2% of yrsSevere drought
10.5 / yr (+9.6)Mid-century 100°F days
14.9 daysMid-century dry spell
2.4" (+7.3%)Mid-century 1-day rain
1.54×Wildfire change factor
100%Forward climate coverage
$2,443Home insurance / yr
2.5% / yrInsurance growth
0.95%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
170,990People within 30 min
4,031,211People within 2 hr
231,229Radius comparison (15 mi)
453.7People / sq mi
0.7%Federal land
71.2%Land at 15% slope or less
14.1%Soils rated "not limited" for septic (strict USDA rating)
52,455 acWorkable land screen
64.3%Wooded land
66 tonsBiomass / forest ac
58.7°FAvg temp

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Cities and towns in Williamson County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

Not yet researched: Fairview · Town of Thompson's Station

Answers from the rulebook for Williamson County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Williamson County rules

  • Building permitRequired

    Locating, erecting, beginning construction, reconstructing, extending, converting, or structurally altering any building or structure in unincorporated Williamson County.

    • The ordinance applies to development of all unincorporated land within Williamson County unless exempted by the ordinance, State law, or Federal law.
    • All necessary approvals for water supply, sewer or septic systems, storm water, and driveways must be issued before the building permit can be issued.
    • A Zoning Certificate must be approved before the building permit can be issued.
    • Required bondable improvements must be completed or appropriate bonds posted before the building permit can be issued.
    • No work may begin before issuance of the Building Permit.
    • Williamson County states that it uses the 2021 International Residential Code, excluding Section B 313.2 and Chapters 34-43 relating to electrical; electrical permits for unincorporated projects are available through the State of Tennessee.
    “Building Permits shall be required before a property owner or applicant can locate, erect, or begin construction, reconstruction, extension, conversion, or structural alteration of any building or structure.”
  • Building code adoptedAdopted (with conditions)

    Building permitting in Williamson County, particularly county-administered unincorporated areas.

    • The 2021 IRC excludes Section R313.2 and Chapters 34-43 relating to electrical; electrical permits for unincorporated projects are available through Tennessee.

    building code edition: 2021 (IBC, IRC, Plumbing Code, and Mechanical Code) · energy code edition: 2018 (2009 tables; effective September 30, 2024)

    “2021 EDITION OF THE INTERNATIONAL BUILDING CODE (IBC)”
    One more reviewed finding on this topic
    • Adopted (with conditions) — Building permitting in Williamson County.
      “In the permitting of buildings, Williamson County uses the following editions of the International Building Code (IBC) 2021 EDITION OF THE INTERNATIONAL BUILDING CODE (IBC) THE 2021 INTERNATIONAL RESIDENTIAL CODE (EXCLUDING SECTION B 313.2, ONE AND TWO DWELLING AUTOMATIC FIRE SPRINKLER SYSTEMS PURSUANT TO T.C.A. 68-120-101 (a)(8), AND CHAPTERS 34-43 RELATING TO ELECTRICAL), THE 2021 INTERNATIONAL PLUMBING CODE THE 2021 INTERNATIONAL MECHANICAL CODE”
  • InspectionsRequired

    Construction inspections during building construction.

    • Inspections include footings, foundation, slab, slab plumbing when applicable, framing, mechanical, and plumbing.
    • The permit applicant is responsible for all work passing inspection.
    • Re-inspections incur an additional $50 fee per re-inspection.

    re-inspection fee: 50 USD (per re-inspection)

    “several inspections must be performed by a County Building Inspector.”
    One more reviewed finding on this topic
    • Required — Construction phases inspected by the Williamson County Building Inspector.
      “During the various phases of construction, several inspections must be performed by a County Building Inspector.”
  • Certificate of occupancyRequired

    Development in regulated flood-hazard areas requiring a Certificate of Compliance/Occupancy.

    • A final Finished Construction Elevation Certificate, FEMA Form 086-0-33, is required after construction and before Certificate of Compliance/Occupancy issuance.
    • The permit holder must submit final as-built elevation certification to the Floodplain Administrator.
    “Certificate of Compliance/Occupancy issuance”
  • County-wide zoningPresent (with conditions)

    Development in unincorporated Williamson County.

    • The ordinance was adopted May 14, 2012 and became effective January 1, 2013.
    • Incorporated municipalities may administer their own local rules.
    “The Zoning Ordinance governs all types of development within the unincorporated areas of the County.”
    One more reviewed finding on this topic
    • Present (with conditions) — Zoning ordinance governing development in unincorporated Williamson County.
      “The Zoning Ordinance governs all types of development within the unincorporated areas of the County.”
  • Local zoningPresent (with conditions)

    All types of development in unincorporated Williamson County.

    • The ordinance applies to unincorporated areas of the County.
    • The county page states that zoning districts regulate allowed land uses, residential density, open space, building setbacks, parking, landscaping, and development-review procedures.
    • Incorporated municipalities may have separate local-government rules.
    “The Zoning Ordinance governs all types of development within the unincorporated areas of the County.”
  • Zoning districtsPublished (with conditions)

    Zoning districts applied to land within unincorporated Williamson County.

    • The county zoning page states that the ordinance establishes a variety of zoning districts.
    • The ordinance contains district-specific dimensional and use standards.
    • The county warns that the ordinance evolves and amendments should be checked with the Planning Department.
    “Establishes a variety of Zoning Districts”
    One more reviewed finding on this topic
    • Published (with conditions) — Zoning districts and map for unincorporated Williamson County.
      “Establishes a variety of Zoning Districts, which are applied to land within the unincorporated County;”
  • Minimum lot sizeDistrict specific (with conditions)

    Residential and nonresidential structures in the zoning districts established by the Williamson County Zoning Ordinance.

    • Minimum lot area varies by zoning district and structure type.
    • The ordinance distinguishes traditional and conservation subdivisions.
    • Where dimensional standards conflict, the most restrictive standards apply.
    • Examples include A district: 15 acres; RP-5 and RD-5 residential structures: 5 acres traditional subdivision, average lot size three-fourths acre and minimum lot size one-fourth acre for conservation subdivisions; RP-1 and RD-1 residential structures: 1 acre traditional subdivision and 10,000 square feet conservation subdivision.
    • The ordinance provides additional village-district standards and exceptions.

    A district minimum lot area: 15 acres (Residential and nonresidential structures) · RP-5 residential traditional subdivision minimum lot area: 5 acres · RP-5 residential conservation subdivision average lot size: 3/4 of an acre · RP-5 residential conservation subdivision minimum lot size: 1/4 of an acre · RP-1 residential traditional subdivision minimum lot area: 1 acre · RP-1 residential conservation subdivision minimum lot area: 10,000 square feet

    “Tables 10.07-1, 10.07-2, and 10.07-3, which begin on the next page, are summary tables of the dimensional standards established for all the zoning districts established in this Article.”
    One more reviewed finding on this topic
    • District specific (with conditions) — Residential structures in the MGA-5 zoning district.
      “DIMENSIONAL STANDARDS RESIDENTIAL STRUCTURES NONRESIDENTIAL STRUCTURES Minimum Lot Area 5 acres 5 acres Maximum Gross Density 1.0 unit per 5 acres Not Applicable Minimum Lot Width 200 feet 130 Feet Front Yard Setback 100 feet 60 Feet Side Yard Setback 20 feet 35 feet Rear Yard Setback 60 feet 60 feet Maximum Height 3.0 stories 3.0 stories”
  • SetbacksDistrict specific (with conditions)

    Front, side, and rear yard setbacks for structures in Williamson County zoning districts.

    • Setbacks vary by zoning district, structure type, subdivision type, and lot-size category.
    • For nonconforming lots, setbacks may be governed by the subdivision plat or the setbacks in place when the lot was created.
    • For lots created before county zoning, lots under 1 acre use Conservation Subdivision RP-1 setbacks and lots of 1 acre or greater use Traditional Subdivision RP-1 setbacks.
    • The ordinance permits specified encroachments, including certain appurtenances up to three feet into setbacks.
    • Where dimensional standards conflict, the most restrictive standards apply.

    RP-1 residential structure front yard setback: 60 feet traditional subdivisions 1-4.99 acres; 100 feet traditional subdivisions 5 acres or greater; 35 feet conservation subdivisions · RP-1 residential structure side yard setback: 20 feet traditional subdivisions 1-4.99 acres; 5 feet conservation subdivisions · RP-1 residential structure rear yard setback: 60 feet traditional subdivisions; 30 feet conservation subdivisions · 840C residential structure setbacks: 60 feet front, 25 feet side, 60 feet rear for traditional subdivisions 1-4.99 acres; 100 feet front and 20 feet side for traditional subdivisions 5 acres or greater; 30 feet rear for conservation subdivisions

    “TABLE 10.07-2: SUMMARY TABLE OF MINIMUM SETBACKS”
    2 more reviewed findings on this topic
    • Specified — Setbacks in unincorporated Williamson County zoning districts, including NCMH and neighborhood-conservation districts.
      “The lot width and setbacks of lots within the NCMH District shall be governed as noted on the recorded final plat of subdivision.”
    • District specific (with conditions) — MGA-5 residential structures and nonconforming or exempt lots under the county zoning ordinance.
      “Minimum Lot Area 5 acres 5 acres Maximum Gross Density 1.0 unit per 5 acres Not Applicable Minimum Lot Width 200 feet 130 Feet Front Yard Setback 100 feet 60 Feet Side Yard Setback 20 feet 35 feet Rear Yard Setback 60 feet 60 feet Maximum Height 3.0 stories 3.0 stories”
  • Lot coverageSpecified

    Mobile-home stands in mobile-home plots under Article 11.

    • The one-third maximum applies to the mobile-home stand relative to its plot.

    maximum mobile home stand coverage: <= 0.33 fraction

    “Mobile home stands shall not occupy an area in excess of one-third of the respective mobile home plot (e.g. the maximum coverage of the mobile home stand to the plot where the mobile home is located shall not exceed 0.33).”
  • Building heightSpecified

    Building height in applicable unincorporated Williamson County zoning districts.

    • Height limits vary by district and use.

    maximum height: 3.0 stories (Triune Character Area-4 residential and nonresidential structures in cited table)

    “Maximum Height 3.0 stories General Notes: [1] The minimum lot size may be reduced to 6,000 square feet for up to 50% of the lots provided that any lot that is less than 8,000 square feet is surrounded by Open Space or lots of 8,000 square feet or greater.”
    One more reviewed finding on this topic
    • Specified — Buildings in unincorporated county zoning districts.
      “Building height shall be measured in number of complete stories above the finished grade for any building.”
  • Living in an RVTemporary only (with conditions)

    Occupancy of a recreational vehicle or travel trailer as temporary shelter while the primary residence is being constructed in unincorporated Williamson County.

    • The Building Permit for the primary residence must be issued before the Temporary Use Permit for the temporary shelter is issued.
    • A Temporary Use Permit may be issued for one year.
    • The Planning Director may grant renewal for one additional six-month period; no renewal may be issued unless construction has begun on the permanent structure.
    • The temporary shelter must meet the setback requirements of the applicable zoning district.
    • The temporary shelter must be served by approved water and sewage disposal facilities.
    • If a mobile home is used, it must meet all standards of Section 11.03:(B)(3): Mobile Homes.
    • The temporary shelter must be removed when residential use ceases or when the occupancy permit for the new principal dwelling is issued, whichever occurs first.
    • The applicant must provide express written consent authorizing Williamson County to remove the shelter at the owner's expense upon termination of the permit.
    • The ordinance applies to development of unincorporated land within Williamson County.

    initial temporary use permit duration: 1 year · permitted renewal periods: 1 six-month period (No renewal unless construction has begun on the permanent structure.)

    “while the primary residence is being constructed [...] A. Recreational vehicles and travel trailers;”
    One more reviewed finding on this topic
    • Temporary only (with conditions) — Occupancy of a recreational vehicle or travel trailer as temporary shelter after fire or natural disaster has rendered a single-family dwelling unfit for human habitation in unincorporated Williamson County.
      “fire or natural disaster has occurred [...] A. Recreational vehicles and travel trailers;”
  • Tiny homesLimited

    Occupancy of a proposed tiny home as a residence in unincorporated Williamson County; the ordinance does not list tiny homes by that term, so the proposed use must be classified under the county use table and applicable zoning district standards.

    • The Williamson County Zoning Ordinance governs development in unincorporated areas; incorporated municipalities may apply their own rules.
    • The parcel's zoning district must be identified because Tables 11.01-1 and 11.01-2 list principal uses allowed in each district.
    • If the tiny home is an unlisted use, the Planning Director may classify it into the existing use type that most closely fits it.
    • Household Living covers residential occupancy of a dwelling unit; examples include detached residential dwellings, manufactured homes, and other structures with self-contained dwelling units.
    • A dwelling or dwelling unit must be a separate, complete housekeeping unit with its own kitchen, sleeping area, and full bathroom facilities; the definition excludes hotels, motels, tents, recreational vehicles, and boarding or lodging houses.
    • If classified as a single-family dwelling, the use remains subject to the applicable district table, use-specific standards, dimensional standards, permits, wastewater requirements, and other ordinance requirements.
    • The ordinance states that it was effective January 1, 2013 and adopted May 14, 2012; the online ordinance is identified as an evolving document and the Planning Department should be checked for amendments.

    ordinance effective date: 2013-01-01 · unlisted-use classification authority: Planning Director

    “If an application is submitted for a use that is not listed [...], the Planning Director is authorized to classify the new or unlisted use”
    2 more reviewed findings on this topic
    • Limited — Occupancy of a tiny home as a primary self-contained residential dwelling in unincorporated Williamson County.
      “Example use types include detached residential dwellings (e.g., single-family dwellings, manufactured homes, and other structures with self-contained dwelling units), attached residential dwellings (e.g., multi-family dwellings and congregate independent living centers), and retirement communities.”
    • Limited — A tiny home used as or proposed as an accessory dwelling unit on a parcel in unincorporated Williamson County.
      “Accessory dwelling units may be constructed within an existing dwelling unit (interior apartment) or as a separate or converted accessory structure (e.g., converted garage, carriage house, or stable). Only one accessory dwelling unit, regardless of the number of principal dwellings located on a single parcel, may be permitted. Accessory dwellings shall be limited in size to 750 square feet or 25 percent of the square footage of the principal dwelling, whichever is greater. In no case shall the accessory dwelling be more than 75 percent of the square footage of the principal dwelling. Accessory dwellings classified as mobile homes by the terms of this Ordinance are only allowable in zoning districts in which mobile homes are allowed.”
  • Manufactured homesLimited

    Manufactured housing in the Neighborhood Conservation Manufactured Housing District.

    • The ordinance describes the district as providing locations for manufactured housing including mobile homes and mobile home parks; district-specific zoning, lot, width, setback, and other requirements apply.

    minimum lot area: 1 acre

    “The purpose of the Neighborhood Conservation Manufactured Housing District (NCMH) is to provide locations for manufactured housing including mobile homes and mobile home parks that are distinct from the other residential zoning districts so as to minimize land use conflicts.”
  • Accessory dwellingsAllowed (with conditions)

    Residential accessory dwelling units in applicable unincorporated county zoning districts.

    • Only one accessory dwelling unit may be permitted per parcel.
    • Size is limited to 750 square feet or 25 percent of the principal dwelling, whichever is greater, but never more than 75 percent of the principal dwelling.
    • Mobile-home accessory dwellings are allowed only in districts allowing mobile homes.
    • A deed restriction must be recorded before obtaining an approved Zoning Certificate and Building Permit.
    • Interior apartments must maintain the exterior appearance of a single-family home and have no second front door.
    • Additions must comply with applicable zoning dimensional requirements.

    maximum number per parcel: 1 unit (regardless of the number of principal dwellings) · size threshold: 750 or 25% square feet or principal-dwelling floor area (whichever is greater; never more than 75% of principal dwelling)

    “Only one accessory dwelling unit, regardless of the number of principal dwellings located on a single parcel, may be permitted.”
    One more reviewed finding on this topic
    • Limited — Accessory dwelling units in unincorporated county zoning districts.
      “Table 11.04-1: Permitted Accessory Uses and Structures lists what types of accessory uses, structures, and activities are allowed in each of the zoning districts.”
  • Who permits septicCounty (with conditions)

    Individual onsite septic and subsurface sewage disposal systems within Williamson County.

    • The County Department of Sewage Disposal Management implements and enforces county septic-system laws.
    • The Department designates the appropriate system type for each property within the county.
    • A valid Construction Permit and Permit to Install are required before applicable construction or installation; exemptions may apply to qualifying property owners or tenants.
    • The regulations state that the current version was amended March 18, 2025 and became effective July 1, 2025.
    “The Department of Sewage Disposal Management is charged with the task of ensuring that the laws of Williamson County regarding the use and placement of individual, onsite septic tank / sewage disposal systems (septic systems), are fairly implemented and enforced so as to protect:”
    One more reviewed finding on this topic
    • County (with conditions) — Individual onsite septic tank and sewage disposal systems in Williamson County.
      “The Department of Sewage Disposal Management is charged with the task of ensuring that the laws of Williamson County regarding the use and placement of individual, onsite septic tank / sewage disposal systems (septic systems), are fairly implemented and enforced so as to protect:”
  • Septic permitRequired

    Construction, alteration, extension, modification, or repair of conventional or alternative subsurface sewage disposal systems.

    • A valid construction permit must be issued by the Department before the listed work occurs.
    • Additional site-specific restrictions and approvals may apply.
    “No person shall construct, alter, extend, modify or repair, either alternative or conventional subsurface sewage disposal systems, within Williamson County, unless he/she holds a valid Construction Permit issued by the Department.”
  • Septic inspectionRequired

    Every subsurface sewage disposal system installation.

    • A layout inspection is required before construction begins.
    • A final inspection is required for every installation; additional soil, drain, trench, or system-specific inspections may apply.
    “A Final Inspection shall be required for each and every subsurface sewage disposal system installation.”
  • Off-grid sanitationLimited

    Pit privies, composting toilets, and other non-sewer sanitation systems.

    • Approved pit privies and composting toilets require Board of Health approval and a restrictive covenant, deed restriction, or owner agreement.
    • A pit privy may not be approved as the primary disposal method for a structure supplied with running water.
    • Pit privies are restricted to parcels exceeding 10.01 acres and parcels without habitable or permanent structures.

    minimum parcel size: > 10.01 acres (Pit privy restrictions)

    “The approved use of pit privies and/or composting toilets shall be subject to approval by the Williamson County Board of Health and shall require the proper implementation of a restrictive covenant, deed restriction and/or agreement by the property owner.”
  • Agricultural exemptionConditional

    Agricultural subdivisions under the Williamson County Subdivision Regulations.

    • An agricultural subdivision consists of three or fewer lots of less than five acres subdivided from a larger tract.
    • Created lots must be at least one acre.
    • Overall density may not exceed one lot per five acres.
    • Agricultural subdivisions cannot involve bondable improvements, a variance petition, or notification of adjacent owners of Planning Commission consideration.
    • A preapplication conference and final plat are required.

    maximum number of lots: <= 3 lots (Agricultural subdivision) · minimum lot size: >= 1 acre (Created agricultural-subdivision lots) · maximum overall density: per 1 lot per 5 acres (Original tract and created lots)

    “exempted from providing the required open space within their boundaries.”
  • Subdividing landRegulated (with conditions)

    Subdivisions subject to Williamson County Subdivision Regulations.

    • Major subdivisions of five or more lots require concept plan, preliminary plat, and final plat steps, with a pre-application conference.
    • Agricultural subdivisions have separate criteria and require a preapplication conference and final plat.
    • Minor subdivisions and access-dependent subdivisions have additional plat notation requirements.
    “Major Subdivisions are those consisting of five (5) or more lots.”
    One more reviewed finding on this topic
    • Regulated (with conditions) — Conservation subdivision development in unincorporated Williamson County.
      “Following approval of a Concept Plan for a Conservation Subdivision by the Planning Commission, the applicant may proceed with Preliminary and Final Plat approvals according to the procedures outlined in the Subdivision Regulations.”
  • Driveway accessRequired

    Lots in county zoning districts and subdivision access arrangements.

    • Unless an access easement exception applies, all lots must abut a public road for at least the minimum lot width required by the applicable zoning district.
    • A driveway easement is 25 feet wide from a public road for ingress and egress to one or more lots.
    • Minor and agricultural subdivisions dependent on an easement require the Private Driveway Notation on the proposed plat.

    driveway easement width: 25 feet (Access easement)

    “Except as provided in Section 17.03: Access Easements, below, all lots shall abut a public road for a distance equal to or greater than the minimum lot width standards shown in Article 10: Zoning Districts.”
  • Building in a floodplainLimited

    Development, encroachments, and structures in areas of special flood hazard and regulatory floodways in unincorporated Williamson County.

    • Where open space is required, areas of special flood hazard and surrounding buffers must be preserved in their natural state as open space; where open space is not required, such areas may be on individual lots but must be preserved and buffered in their natural state.
    • Fill or other encroachments may not change the predevelopment limits of areas of special flood hazard except as provided in the ordinance.
    • Permitted uses as a matter of right include open-space uses, agricultural uses subject to the stated accessory-building limitation, specified recreation uses without buildings except dugouts, bleachers, and stages, bridges, bridge approaches, pump stations, subsurface and nontraditional wastewater fields, boat-launching ramps, docks, piers, marinas, picnic shelters, boathouses, single-family driveways, and off-street parking.
    • Encroachments, permitted new structures, or substantial improvements require registered-professional-engineer certification showing no increase in base-flood water-surface elevation, one-to-one qualified cut offset for fill or other encroachment, and supporting technical data conforming to standard hydraulic engineering principles.
    • For lots of record existing before April 1, 1981, the County Engineer may allow one single-family residence, customary accessory structures, and residential additions only if no suitable building site exists outside the hazard area and the ordinance's permit, flood-hazard-reduction, certification, and cut-offset requirements are met.
    • In regulatory floodways, encroachments are prohibited except as allowed by Section 13.05(H)(1)-(6); permitted development requires hydrologic and hydraulic analysis demonstrating no increase in base-flood elevation, velocities, or floodway widths and certification by a Tennessee registered professional engineer.
    • In Zone AE areas without designated floodways, encroachments require Tennessee-registered-professional-engineer certification that the cumulative development will not increase the base-flood water-surface elevation.
    • In approximate A Zones without established base-flood data, developments over 50 lots or 5 acres, whichever is lesser, must include base-flood-elevation data; absent available data, buildings must be elevated or floodproofed at least 3 feet above the highest adjacent grade.
    • Recreational vehicles in identified special flood hazard areas must be on site fewer than 180 consecutive days, be fully licensed and ready for highway use, or meet all new-construction requirements.

    approximate A Zone development threshold: > 50 lots (The requirement also applies to developments greater than 5 acres, whichever is lesser.) · approximate A Zone development threshold: > 5 acres (The requirement applies when greater than 50 lots or 5 acres, whichever is lesser.) · approximate A Zone elevation/floodproofing: 3 feet above highest adjacent grade (Applies where base-flood data has not been established and is unavailable from other sources.) · recreational vehicle site duration: < 180 consecutive days (Alternatively, the vehicle must be fully licensed and ready for highway use or meet all new-construction requirements.)

    “For properties that contain areas of special flood hazard as defined by the Ordinance, the following shall apply: [...] Under no circumstances shall fill material or other encroachments be permitted so as to change the predevelopment limits of any areas of Special Flood Hazard, except where provided herein.”
    One more reviewed finding on this topic
    • Required — Development activities on properties containing areas of special flood hazard in unincorporated Williamson County.
      “The provisions of this Ordinance shall apply to the development of all unincorporated land within the boundaries of Williamson County, Tennessee unless exempted by this Ordinance, State law, or Federal law. [...] Application for a Zoning Certificate shall be made to the Administrator on forms furnished by the County prior to any development activities.”
  • Permit feesPublished

    County building permits.

    • The county page provides a downloadable complete and current fees-and-requirements document.
    • Separate checks are required for building permits and privilege taxes.
    “Download the complete and current fees and requirements.”
    One more reviewed finding on this topic
    • Published (with conditions) — County building permits and related permit costs.
      “Download the complete and current fees and requirements.”
  • Permit processPublished (with conditions)

    County building and other necessary permits.

    • Applications may be completed online through Williamson County's Electronic Plan Review System.
    • The Building Codes Department provides additional information by telephone.
    “Building and other necessary permits may be completed online”
    One more reviewed finding on this topic
    • Published (with conditions) — County building-permit application process.
      “Building and other necessary permits may be completed online using Williamson County's Electronic Plan Review System.”

Tennessee rules that apply here

  • Owner-builder exemptionAvailable (with conditions)

    An owner constructing a single residence in Tennessee for the owner's own use.

    • The owner may construct only one single residence once every two years.
    • The residence must be for the owner's own use.
    • The residence may not be for resale, lease, or rent.
    • This is an exemption from contractor-licensing requirements, not an exemption from applicable building permits or local ordinances.
    • Anyone hired by the homeowner whose portion is $25,000 or more is not exempt from Tennessee contractor-licensing requirements.
    • Williamson County is listed by the Tennessee State Fire Marshal's Office as an EXEMPT jurisdiction from the State Residential Building Program as of 2026-08-21; county building-permit and local-code requirements still apply.

    frequency: once every two years · hired contractor threshold: >= 25000 USD (The hired person's portion is not exempt from contractor-licensing requirements.)

    “Yes. Pursuant to TCA § 62-6-103, an owner of property may construct a single residence once every two years for his/her own use, as long as it is not for resale, lease or rent without being a licensed contractor. However, anyone hired by the homeowner whose portion is $25,000 or more would not be exempt from the contractors’ licensing requirements.”
    One more reviewed finding on this topic
    • Conditional — A Tennessee property owner constructing a single residence for the owner's individual use.
      “one permit every two years to build their home as long as it is not for sale, lease, or rent (individual use).”
  • Camping on your landLimited

    Overnight camping on Tennessee Wildlife Resources Agency-controlled Wildlife Management Areas and related lands where overnight camping is allowed.

    • Overnight camping may be permitted only in designated areas and by permission from the area manager, park ranger, lake manager, park superintendent, or national forest supervisor.
    • Camping is subject to limitations prescribed in the permit if required.
    • Camping may not exceed three weeks from the beginning to the end of the camping stay.
    • Owner contact information or a TWRA ID number and date of arrival must be displayed on a camper, tent, vehicle, or similar item at all times.
    • Where overnight camping is allowed, firearms and archery equipment must remain in camp except during legal hunting hours.

    maximum camping stay: <= 3 weeks

    “May be permitted in designated areas by permission from the area manager, park ranger, lake manager, park superintendent, or national forest supervisor. Such camping is subject to the limitations prescribed in the permit if required.”
    One more reviewed finding on this topic
    • Limited — Camping and use of trailers or other camper units in Tennessee state forests administered by the Tennessee Department of Agriculture, Division of Forestry.
      “Camping and the use of trailers or other camper units are allowed only at designated locations. The district forester will issue written permits to persons to camp in backcountry or other isolated sections of a forest area.”
  • Mandatory utility hookupConditional

    Connection of buildings to sanitary sewer systems where a qualifying Tennessee utility system has issued bonds payable for sewer services and the property abuts a street or public way containing a sanitary sewer.

    • The property must abut a street or other public way containing a sanitary sewer.
    • A building must exist on the lot or parcel for residential, commercial, or industrial use.
    • The utility system may require connection and cessation of other sewage-disposal methods.
    • For electrical service, written notification must show public sewer service, a septic permit application, or an existing septic system.
    “Utility systems within the State of Tennessee that have issued bonds payable for sewer services are granted authority in TCA § 7-35-201 (1) to "require the owner tenant or occupant of each lot or parcel of land that abuts upon a street or other public way containing a sanitary sewer and upon which lot or parcel a building exists for residential, commercial or industrial use, to connect the building with the sanitary sewer and to cease to use any other means for the disposal of sewage, sewage waste or other polluting matter."”
    One more reviewed finding on this topic
    • Sewer (with conditions) — Residential, commercial, or industrial buildings on lots or parcels abutting a street or other public way containing a sanitary sewer, where the applicable Tennessee utility system has issued bonds payable for sewer services.
      “Utility systems within the State of Tennessee that have issued bonds payable for sewer services are granted authority in TCA § 7-35-201 (1) to "require the owner tenant or occupant of each lot or parcel of land that abuts upon a street or other public way containing a sanitary sewer and upon which lot or parcel a building exists for residential, commercial or industrial use, to connect the building with the sanitary sewer and to cease to use any other means for the disposal of sewage, sewage waste or other polluting matter."”
  • county zoning authorityGeneral

    County legislative bodies adopting zoning regulations for portions of Tennessee counties outside municipal corporations.

    • The authority is exercised under the conditions and procedures in Tennessee Code Annotated §§ 13-7-101 through 13-7-119.
    • The grant applies to portions of counties outside municipal corporations.
    • County zoning authority does not authorize county building permits or regulation of buildings or structures on agricultural land when the building or structure is incidental to the agricultural enterprise, except on agricultural lands adjacent or in proximity to state federal-aid highways, public airports or public parks.
    • The agricultural-land limitation applies to counties only and has no application to municipalities.
    “Under Tenn. Code Ann. § 13-7-101, et seq., the General Assembly has expressly delegated the authority to county legislative bodies to enact zoning regulations and create a board of zoning appeals.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Minimum dwelling size — Minimum dwelling size in county zoning districts.
  • Well permit — Private water wells.
  • Short-term rentals — Short-term rental or visitor-accommodation use.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Living off-grid in Williamson County, Tennessee

Is Williamson County a good place to live off-grid or homestead?

Williamson County scores 58/100 on the Bolthole Index, a solid county profile. Its strengths: strong self-sufficiency basics: 53.5″/yr rainfall plus 64.3% wooded land and mixed durability signals. Watch-outs: about 170,990 people within a 30-minute drive.

Do you need a building permit in Williamson County, Tennessee?

Williamson County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Williamson County (contract county for SSDS under TDEC). Owner-builders may act as their own contractor to build their home. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

Can you live in an RV or tiny home on your land in Williamson County?

Living in an RV on your own land in Williamson County is allowed on a temporary basis only: Occupancy of a recreational vehicle or travel trailer as temporary shelter while the primary residence is being constructed in unincorporated Williamson County. The Building Permit for the primary residence must be issued before the Temporary Use Permit for the temporary shelter is issued. A Temporary Use Permit may be issued for one year. A tiny home is limited to specific cases. Confirm with the county before relying on it.

How much does land cost in Williamson County, Tennessee?

Land in Williamson County runs about $7,148 per acre, based on the latest county data.

What is the water situation in Williamson County?

Williamson County gets about 53.5" of rain a year, with severe drought in roughly 3.2% of years.

How remote is Williamson County?

A representative private-land location has about 170,990 people within a 30-minute drive and 4,031,211 within two hours. The road-network catchments count population across county lines and clusters of smaller cities; straight-line radius values remain available as a comparison.

How Williamson compares in Tennessee

Compare side-by-side →See all 95 Tennessee counties ranked →