Union County, Tennessee requires a building permit, and the county Assessor of Property sells permits for new construction in person rather than online.12 Union County also has its own zoning, so rural land is not unrestricted, but parcel-specific districts and standards should be confirmed before buying.3 Septic permits are not a county matter: TDEC's Knoxville Environmental Field Office handles them for every address in Union County.45
At a glance
- Building permit
- Required; purchase it in person from the Union County Assessor of Property (state residential program does not apply)126
- Zoning
- Yes; confirm the parcel's district and allowed use with Union County before designing3
- Septic permit
- Required for a new system or repair and administered by TDEC47
- Owner-builder
- Allowed for your own residence if not sold or leased and no homeowner permit in the prior 24 months8
- RV living
- Not confirmed; ask the county about the parcel and intended length of stay3
- Tiny home
- Not confirmed; ask the county about zoning, minimum size and occupancy approval3
- Septic soil difficulty
- Only about 11.4% of soils lack severe limits for a conventional drain field9
- Property tax
- Effective rate about 0.4%; median annual bill about $7201011
Who to call
Building permits
Union County Assessor of Property
Building permits and 911 addresses for new construction in Union County
randy.turner@unioncountytn.gov
901 Main Street, Suite 106, Maynardville, TN 37807
Septic permits
TDEC Knoxville Environmental Field Office
Septic-related inquiries, applications and inspection coordination for Union County
3711 Middlebrook Pike, Suite 101, Knoxville, TN 37921
Contact details are copied from each office’s official page and were checked against it on October 10, 2026.
Off-grid gear
Going off-grid in Union County means bringing your own water and power. The kit we’d start with:
- Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
- Power Bluetti Solar generators and home battery backup for living off the grid.
- Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
- Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.
These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.
Do you need a building permit in Union County, Tennessee?
Yes. Union County requires building permits, and the Assessor of Property says every county building permit must be purchased in that office.12 The office sells permits for new construction, assigns 911 addresses for new construction, and does not offer its building permits online.2
The available information does not establish which locally adopted building code applies, what inspections follow, or whether a certificate of occupancy is required. Ask the Assessor of Property to identify the current code official, required inspections, permit fee and closeout documents for the exact project before work begins. Tennessee's Fire Marshal lists Union County as exempt from the State Residential Building Program, which means the state does not run residential permitting here; that listing does not establish whether Union County has a local building code or what it requires.612
Who issues Union County building permits, and how do you reach the office?
The Union County Assessor of Property is the practical first stop for a house or other new construction because the office sells the county's building permits and assigns new-construction 911 addresses.2 Visit the Assessor of Property at 901 Main Street, Suite 106, Maynardville, or call the published office number before making the trip.2 Permits are not offered online.2
Ask the office what plans and site documents to bring, how the fee is calculated, which inspections apply, and who reviews zoning. Union County's published information confirms the permit-sales role, but we could not confirm a separate county building department, inspection schedule or current fee schedule. The distinction matters because Tennessee's state residential program does not replace local zoning, septic, floodplain, grading or electrical approvals.12
Does Union County, Tennessee have zoning?
Union County has adopted zoning and subdivision regulations, so rural land should not be treated as unrestricted.3 Tennessee law allows counties to zone land outside municipal corporations, while incorporated places may administer their own rules.13 Union County maintains a Planning & Zoning Coordinator, so that is the office to ask about the parcel.3 Dividing a tract into two or more lots where a septic system will be used also triggers a state subdivision evaluation by TDEC, unless every resulting parcel is 5 acres or larger.14 Before relying on a listing or a seller's description, ask Union County which jurisdiction and zoning district cover the parcel and whether the proposed dwelling, accessory building or business use is allowed.
We could not confirm a current official district schedule for setbacks, minimum dwelling size, minimum lot size, lot coverage or building height. Ask for a written zoning determination tied to the parcel, particularly for a tiny home, manufactured home, accessory dwelling or long-term RV use. A qualifying agricultural structure may receive protection from county zoning only when it is on land devoted to agricultural use and incidental to the agricultural enterprise, subject to stated location and floodplain exceptions.15
How do septic permits work in Union County?
TDEC administers septic permitting for Union County through the Knoxville Environmental Field Office.165 Union County is not among the contract counties that may require an additional local septic permit, and a septic permit applies to a new system, a modification or a repair.1718 Obtain that approval before dirt work or construction begins, including preparation of a building pad.19
TDEC evaluates the site and may request a site plan, soil map or engineered design; processing can take up to 45 days after a complete application arrives.20 The installer must arrange the final inspection before covering the system, and TDEC issues a Certificate of Completion after approval.21 Only about 11.4% of Union County soils lack severe limits for a conventional drain field, so make septic feasibility an early purchase contingency rather than assuming a conventional layout will work.9 Electrical-service processing also requires written notice of public sewer service, a septic application or use of an existing system.22
Can you live in an RV or tiny home in Union County?
We could not confirm a Union County rule that allows or prohibits living in an RV on private land, temporary camping, tiny-home occupancy, manufactured-home occupancy or accessory dwellings. Because Union County has zoning, a small structure or vehicle is not automatically approved as a residence merely because the land is rural.3 Ask the county for a parcel-specific answer covering the proposed use, duration, utility connections, setbacks and any required occupancy approval.
A tiny home used as a dwelling still needs a workable sanitation path: installation of a septic system or repair of a faulty system requires a TDEC construction permit.7 For an owner-built residence, Tennessee allows a homeowner to build a home as their own residence, but it cannot be sold or leased, and the homeowner cannot have been issued a homeowner building permit in the prior 24 months.8 That contractor-licensing exception does not itself settle zoning, building-code, septic or RV-occupancy questions.
Building a home in Union County: what are the steps?
- Ask Union County to confirm the parcel's jurisdiction, zoning district, allowed dwelling type and dimensional standards; the county has zoning, but the current parcel-level standards were not confirmed.3
- Establish septic feasibility and apply through TDEC before grading or preparing the building pad; a septic construction permit is required for a new system or repair.19
- Obtain the 911 address and purchase the Union County building permit in person from the Assessor of Property.2
- Ask which locally required inspections and electrical approvals apply; electrical-service processing requires sewer or septic documentation.22
- If the driveway connects to a Tennessee state highway right-of-way, obtain the required TDOT highway entrance permit before constructing or changing it.23
- Have the septic installer schedule TDEC's final inspection before covering the system and retain the Certificate of Completion after approval.21
What should you check before buying land in Union County?
Start with buildability, not the asking price. Only about 21.9% of Union County land is at a slope of 15% or less, and about 70.2% is wooded, so verify the actual homesite, access grade and clearing needs on the parcel.2425 Septic deserves equal attention because only about 11.4% of soils lack severe limitations for a conventional drain field.9
Confirm the zoning district, setbacks and permitted dwelling type with the county because Union County has zoning but the current district details were not confirmed.3 Check whether the site lies in a flood hazard area and ask the county who handles development approval there. A driveway on state highway right-of-way requires TDOT approval, while a county-road entrance should be discussed with the county before construction.23 For budgeting context, the effective property-tax rate is about 0.4%, and the median annual property-tax bill is about $720.1011
Watch-outs
- Union County building permits must be purchased in person; the Assessor of Property does not offer them online.2
- Do not start dirt work or prepare the building pad before obtaining the applicable septic approval.19
- Union County's RV, tiny-home, setbacks, minimum-size and floodplain procedures remain unconfirmed; ask the county for parcel-specific written answers before closing.3
- A state-highway driveway requires a TDOT entrance permit even when other county approvals are already in hand.23
Sources
- Union County Assessor of Property (2026 county census)
- Union County Assessor of Property (unioncountytn.gov)
- Union County Subdivision Regulations (2026 county census)
- TDEC - Subsurface Sewage Disposal Systems (SSDS) (2026 county census)
- TDEC Knoxville Environmental Field Office (tn.gov)
- Tennessee Fire Marshal's Office Residential Permits Residential Jurisdictions & Inspectors, quoted and re-checked
- Septic System Construction Permit (Tennessee statewide rule), quoted and re-checked
- Residential Permits, quoted and re-checked
- 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
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
- Residential Permit FAQs (Tennessee statewide rule), quoted and re-checked
- Tennessee Attorney General Opinion No. 10-108 (Tennessee statewide rule), quoted and re-checked
- Online Application for Septic Related Services, quoted and re-checked
- Exemption from County Zoning Regulation for Buildings on Land Used for Agriculture, Opinion No. 22-07 (Tennessee statewide rule), quoted and re-checked
- Subsurface Sewage Disposal System Frequently Asked Questions, quoted and re-checked
- Online Application for Septic Related Services, quoted and re-checked
- Online Application for Septic Related Services, quoted and re-checked
- Subsurface Sewage Disposal System Frequently Asked Questions, quoted and re-checked
- Subsurface Sewage Disposal System Frequently Asked Questions, quoted and re-checked
- Subsurface Sewage Disposal System Frequently Asked Questions, quoted and re-checked
- Online Application for Septic Related Services, quoted and re-checked
- Highway Entrance Permits (Tennessee statewide rule), quoted and re-checked
- Share of land at 15% slope or less: Bolthole Index county data
- Wooded share of land: Bolthole Index county data
Written October 10, 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.