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

Unincorporated Knox County requires a written building permit before erecting, structurally altering or moving a building or structure, or changing a building or land use¹. Maintenance and interior finishes in houses, attached houses and duplexes are exempt, as are agricultural uses and accessory farm buildings¹. That exemption is only from the written building-permit requirement, not every county, state, health or environmental rule¹. A main-building permit covers accessory buildings built at the same time; a separately built accessory structure needs its own permit¹. Knox County publishes a fee schedule, but the available material does not provide usable current amounts; starting covered construction before obtaining the permit doubles the fee^1,7.

Inside Farragut, the town handles building permits for new construction and most remodeling⁸. Septic permits remain with Knox County Health Department Groundwater Protection throughout the county².

Knox County Codes Administration & Inspection accepts applications at 400 Main Street, Suite 547, Knoxville, TN 37902; call 865-215-2325 or email code.admin@knoxcounty.org⁹. Applications are accepted from 8:00 a.m. to 4:00 p.m., and an online submission can avoid an office visit⁷. Bring structure drawings and a site plan; commercial plans must bear the stamp of a Tennessee-licensed architect or engineer⁷. The county also requires a certified address sheet, while a septic dwelling needs a Health Department drainfield layout and an addition or accessory building needs septic certification⁷. County materials include amendments to the 2018 International Residential Code, but do not establish every currently adopted construction code¹⁰.

Knox County zoning applies to unincorporated land outside Knoxville and Farragut¹. Knoxville and Farragut administer their own zoning; septic systems in either municipality remain under Knox County Health Department Groundwater Protection^2,11,12.

In unincorporated Knox County's RAE and RA districts, main and accessory buildings together may cover no more than 30% of lot area; PR allows buildings to cover up to 50% of gross site acreage^1,4. In RA, dwellings generally need a 35-foot front yard, side yards of 8 feet for a single-story house on an interior lot or 12 feet for taller houses, and a 25-foot rear yard for the main building¹³. Minimum RA lot size is 10,000 square feet for a sewer-served house and 20,000 square feet for a house on septic, or more if the health department recommends it¹³.

Certain agricultural uses permissible under Tennessee law and compliant with state regulations are exempt from planning commission review⁴. A change of building or land use to the same or a more restricted classification requires a use-and-occupancy permit¹.

Knox County Health Department Groundwater Protection administers local subsurface sewage disposal services under Tennessee regulations². The division issues septic permits when needed for new builds, remodels and repairs, and a soil map or site plan may be needed for the system or drain-field layout². A septic permit is required to construct, modify or repair a system and should be obtained before dirt work or construction of the building pad begins¹⁴. A residential or commercial facility not connected to public sewer must use an SSDS for all wastewater it generates². Contact Groundwater Protection at 865-215-5200². Only 25.5% of Knox County land is rated without severe limitations for a conventional drain field, so settle soil suitability early¹⁵.

An RV stored on a residential-zone lot occupied by a dwelling may not be occupied on the site⁴. That storage rule permits one camping or travel trailer, recreational vehicle, hauling trailer or boat trailer per household, no longer than 40 feet or wider than 10 feet, behind the front building line⁴. We could not confirm a complete rule for temporary camping elsewhere on private land, so ask Knox County Codes Administration & Inspection what the parcel's mapped district permits^1,9. Mobile homes are listed as permitted uses in the RA and RB residential districts of unincorporated Knox County, and mobile-home parks need planning commission approval¹. That permission does not extend to every district⁴. Knox County's adopted residential building code includes Appendix Q, Tiny Houses, which gives a building-code pathway for a tiny house, but it does not by itself make a tiny home allowed in every zoning district; zoning, permits, sewage disposal and inspections still apply⁵. A tiny home is also not permit-exempt because of size, since the county permit rule applies to erecting, structurally altering or moving buildings and structures¹.

1. Confirm that the parcel is outside Knoxville or Farragut, then identify its county zoning district¹.

1. Determine whether public sewer is available; a facility without sewer must have an SSDS².

1. Obtain the septic permit before dirt work or building-pad construction, then secure the drainfield layout or certification required for the project^7,14.

1. Obtain a certified address, prepare the site plan and drawings, and apply through Codes Administration⁷.

1. Resolve access: county driveway policy applies with a building-permit application, while a state-highway connection needs TDOT approval^1,6.

1. A homeowner-builder may construct one residence every two years for personal use, not resale, lease or rent, and must use the county affidavit and comply with its licensing and insurance conditions³.

Before buying land in Knox County, verify jurisdiction and the mapped zoning district¹. Conventional septic suitability deserves early attention because only 25.5% of county land is rated without severe drain-field limitations¹⁵. Terrain and clearing affect costs: 55.4% of land has a slope of 15% or less, and 65.9% is wooded¹⁵. The USDA farmland value is $12,302 per acre, while the median annual property-tax bill is $1,332 and the effective rate is 0.5%¹⁵. We could not confirm Knox County’s floodplain-development or private-well permit requirements; ask Codes Administration about floodplain review and Groundwater Protection about private wells^2,9.