Thompson's Station sits between Franklin and Spring Hill in southern Williamson County. Its housing is mostly newer subdivisions and larger rural lots, with some older homes mixed in. The town runs its own building and codes office and has a few rules that homeowners and contractors trip over, especially for water heaters and furnaces.
The code editions in force
Under Ordinance 2024-007, Thompson's Station began enforcing these codes on January 1, 2025:
| Code | Edition |
|---|---|
| International Residential Code | 2021 |
| International Building Code | 2021 |
| International Fire, Plumbing and Mechanical Codes | 2021 |
| International Property Maintenance, Swimming Pool and Spa, and Existing Building Codes | 2021 |
| International Energy Conservation Code | 2018 |
| National Electrical Code | 2023 |
| NFPA 101 Life Safety Code | 2018 |
That mix of editions matters. The residential code is 2021, the energy code is 2018 and the electrical code is 2023. Designers who work across several towns need to check each one.
The gas-vent PVC rule
This one is specific and comes up often. The town has posted a notice that schedule 40 solid-core PVC is not approved for venting fuel-fired appliances, even where a water heater manufacturer lists it as an option. The town's reasoning: PVC manufacturers say standard PVC fails as a gas vent, standard schedule 40 PVC breaks down at 140 degrees, and a typical gas water heater exhausts at 148 degrees.
The rule:
- the gas vent pipe must be stamped UL 1738, or the manufacturer must document that the pipe is UL 1738 approved;
- if you rely on documentation, the pipe must carry the manufacturer's mark so it can be tied to that documentation;
- inspectors check the exhaust pipe at the mechanical rough-in inspection.
If you're replacing a gas water heater or a high-efficiency furnace, ask your plumber or HVAC contractor what vent pipe they'll use before the job, not after a failed inspection. See HVAC.
This is also a good moment to consider a heat pump water heater, which doesn't need a combustion vent at all. TVA EnergyRight lists a rebate for qualifying heat pump water heaters through local power companies. Check current terms.
Permits and hours
The town uses the GeoCivix electronic system for planning applications, permits and inspection requests. You upload the documents on the checklist for your project type, and you'll get an email saying whether it was accepted, then another when review is done. Applications that are missing checklist documents won't be reviewed. A permit isn't issued until both the Town Planner and the Building Codes Official have signed off. The portal lists minor property improvements such as porches, patios, decks, sheds, retaining walls, driveways and detached garages. The town also publishes third-party plan review and inspection procedures. Town Hall is at 615-794-4333, open 8:30 to 4:30 on weekdays.
Construction hours under the town's municipal code are 7 a.m. to 6 p.m., Monday through Saturday, excluding federal holidays. Tell your contractor, especially for loud work like roofing.
Blasting for construction is permitted and monitored by the Tennessee State Fire Marshal's Office, not the town. If a pool or foundation dig hits rock, that's who regulates it.
Projects that fit Thompson's Station homes
Finishing space. Many newer houses have bonus rooms or basements left unfinished. See home additions.
Outdoor living. Covered patios, screened porches and decks are common on larger lots. HOA approval usually comes first. See decks and porches.
Kitchen and bath updates. Builder-grade finishes often get replaced early. See kitchen remodeling and bathroom remodeling.
Roofs. Hail and wind are the main threats. Newer homes are often on their first roof. See roofing.
Windows and paint. Newer homes may need little window work, but older houses built before 1978 call for lead-safe practices when painting or replacing windows. See windows and exterior painting.
HOAs
Most of Thompson's Station's newer neighborhoods are governed by HOAs with design guidelines. Get written approval before you apply for town permits for fences, exterior colors, additions, pools and outdoor structures.
Licensing
Williamson County hasn't adopted Tennessee's Home Improvement license law, so state licensing for general remodeling starts at $25,000, when a contractor's license is required. Plumbing, electrical and HVAC trades have their own rules. Verify any license on the state's Verify search.
Services we match in Thompson's Station
- HVAC — Heat pumps, furnaces and AC.
- Home Additions — Primary suites, second stories and ADUs (DADUs).
- Decks & Porches — Covered porches, screened porches and decks.
- Kitchen Remodeling — Bungalow kitchens, open layouts and new finishes.
- Bathroom Remodeling — Shower conversions, primary baths and updates.
- Roofing & Storm Repair — Roof replacement, wind and hail damage, tarping.
- Window Replacement — Replacement windows and historic window repair.
- Exterior Painting — Siding, trim and brick painting.
Thompson's Station homeowner questions
Can my plumber vent a new gas water heater with schedule 40 PVC?
Not in Thompson's Station. The town requires gas vent pipe stamped UL 1738, or manufacturer documentation that it's UL 1738 approved. It's checked at the mechanical rough-in inspection.
Which residential code does the town use?
The 2021 International Residential Code, enforced since January 1, 2025, along with the 2018 energy code and the 2023 National Electrical Code.
What are construction hours?
7 a.m. to 6 p.m., Monday through Saturday, excluding federal holidays.
Does the town regulate blasting?
No. Construction blasting is permitted and monitored by the Tennessee State Fire Marshal's Office.
Nearby areas
Spring Hill · Franklin · Columbia
Guides for Thompson's Station homeowners
Sources
Checked by the Nashville Home Projects editorial team on October 20, 2026. Rules and prices change, so confirm details with the agency or your contractor before you sign.