Solar Permit in Williamson County, Tennessee
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Issued byWilliamson County Building Codes Department
By Mario Bailey, verified against official sources
Quick answer
Williamson County's Zoning Ordinance Section 11.04(D)(12) confirms that solar panels attached to a principal building or accessory structure are a permitted accessory use and shall not require a Zoning Certificate, provided panel height meets the applicable zoning district's height limit. That provision addresses zoning approval only. Whether a rooftop or ground-mounted solar PV installation requires a building or electrical permit from Williamson County Building Codes, or must be routed through the state CORE electrical permit system the way other unincorporated-county electrical work is (see Electrical Permit), was not confirmed on any Building Codes Department page. Contact the Building Codes Department at 615-790-5718 or the state CORE system at core.tn.gov before installing solar panels.
Applying yourself? Start with the office.
What a solar permit costs in Williamson County
How Williamson County compares in Tennessee
No Tennessee jurisdiction we have verified sets a size threshold for this permit, so what actually differs between them is the fee.
How to apply in Williamson County
In Williamson County, a rooftop solar PV permit application is a combined structural and electrical plan set: a site plan and roof framing details proving the array's mounting can carry its added loads, plus a one line electrical diagram covering listed modules and inverters, disconnects, and the rapid shutdown design. Utility interconnection is a separate approval that runs in parallel with the permit.
What most solar permit applications include:
- Both a building permit and a separate electrical permit are required, since the array must be designed and installed to the residential code's solar provisions and to the National Electrical Code (IRC R324.3).
- For Williamson County, the plan set identifies listed equipment: PV modules listed to UL 1703 (or both UL 61730-1 and UL 61730-2), and inverters listed to UL 1741, with grid-tied inverters listed for utility interaction (IRC R324.3.1).
- Structural drawings show that the roof framing is designed to structurally support the array and withstand the gravity loads it adds (IRC R324.4.1).
- For Williamson County, the site plan lays out roof access pathways at least 36 inches wide, plus a ridge setback sized to how much of the roof the array covers, so firefighters retain pathways and ventilation access (IRC R324.6.1, IRC R324.6.2).
- For Williamson County, the one line electrical diagram shows the rapid shutdown method and the location of its single initiation device, since one control point must bring all system conductors down to safe levels (NEC 690.12, NEC 690.56(C)).
- Interconnecting the array to the utility grid at a defined point of connection is a separate application process from the local building or electrical permit and must be approved before the system can operate (NEC 705.12).
- Some permitting offices route applications through SolarAPP+, an automated review platform that checks the plan set against code requirements and issues eligible permits instantly (DOE SolarAPP+).
General submittal guidance from IRC 2021 R324 (Solar Energy Systems) and NEC 2020 Article 690 (Solar Photovoltaic Systems) and Article 705 (Interconnected Power Production Sources). Source. Williamson County Building Codes Department sets the exact checklist for Williamson County.
Where to apply in Williamson County:
Williamson County Building Codes Department
- 1320 West Main Street, Suite 400, Franklin, TN 37064
- Phone: 615-790-5718
Solar Permit in Williamson County compared with nearby Tennessee localities
| Locality | Permit needed? | Threshold | What each Tennessee schedule says | Verified |
|---|---|---|---|---|
| Williamson County | Not confirmed | Not specified | The structural mounting permit bills under the Section B101 valuation table starting at... | |
| Memphis | Permit required | Not specified | No solar line item. | |
| Nashville | Permit required | Not specified | $75 minimum permit fee |
Inspections and closing out your permit
In Williamson County, inspectors verify the installed array against the approved plans, and some agencies run a rough check of roof attachments and penetrations while they are still exposed before the wiring and roofing close them in. The final inspection confirms rapid shutdown, disconnects, grounding, and required labels are installed correctly, and the system cannot be energized until the utility separately approves interconnection.
- In Williamson County: where an agency runs a rough or pre-inspection, it checks the array's roof penetrations while they are still exposed, confirming they are flashed and sealed (IRC R324.4.3).
- In Williamson County: the inspector confirms whether rapid shutdown is required, how it is accomplished, and that it is properly identified (NEC 690.12, NEC 690.56(C)).
- In Williamson County: pV disconnecting means must be permanently marked and installed where they are readily accessible, which the inspector confirms in the field (NEC 690.13).
- In Williamson County: bonding and grounding of the array, including every exposed non current carrying metal part and the grounding electrode system, is checked before sign off (NEC 690.43, NEC 690.47).
- In Williamson County: at the service equipment, the inspector looks for the required rapid shutdown placard, a labeled diagram showing the initiation device's location in the specified colors and letter sizes (NEC 690.56(C)).
- In Williamson County: utility interconnection is inspected and approved separately from the local building department's sign off, and the system cannot be energized until both approvals are in hand (NEC 705.12).
Schedule each inspection in advance and pass the final before you use the work or close the permit. Request inspections through the Williamson County permit portal or by phone at 615-790-5718.
Inspection sequence from NEC 2020 Article 690 (690.12 rapid shutdown, 690.13 disconnects, 690.43/690.47 grounding, 690.56 labeling) and IRC 2021 R324.4.3 (roof penetrations). Source. An open permit left un-inspected can surface later in a title search or home sale.
Your Solar Permit checklist for Williamson County
- Confirm the requirement. Not confirmed, contact the office.
- Budget the fee. The structural mounting permit bills under the Section B101 valuation table starting at $15 for the first $1,000 plus $5 per additional thousand; the PV electrical connection is permitted separately through the state CORE system, per the county Schedule of Building Permit Fees. Official fee schedule.
- Apply. In Williamson County, a rooftop solar PV permit application is a combined structural and electrical plan set: a site plan and roof framing details proving the array's mounting can carry its added loads, plus a one line electrical diagram covering listed modules and inverters, disconnects, and the rapid shutdown design. Utility interconnection is a separate approval that runs in parallel with the permit. Start at the Williamson County permit portal.
- Keep the office details handy. Williamson County Building Codes Department. Phone: 615-790-5718. Address: 1320 West Main Street, Suite 400, Franklin, TN 37064.
- Plan for inspections. In Williamson County, inspectors verify the installed array against the approved plans, and some agencies run a rough check of roof attachments and penetrations while they are still exposed before the wiring and roofing close them in. The final inspection confirms rapid shutdown, disconnects, grounding, and required labels are installed correctly, and the system cannot be energized until the utility separately approves interconnection.
Compiled from the official sources on this page. Last checked .
Frequently asked questions
- Do you need a solar permit in Williamson County?
- Williamson County's Zoning Ordinance Section 11.04(D)(12) confirms that solar panels attached to a principal building or accessory structure are a permitted accessory use and shall not require a Zoning Certificate, provided panel height meets the applicable zoning district's height limit. That provision addresses zoning approval only. Whether a rooftop or ground-mounted solar PV installation requires a building or electrical permit from Williamson County Building Codes, or must be routed through the state CORE electrical permit system the way other unincorporated-county electrical work is (see Electrical Permit), was not confirmed on any Building Codes Department page. Contact the Building Codes Department at 615-790-5718 or the state CORE system at core.tn.gov before installing solar panels. Always confirm with the Williamson County Building Codes Department before starting.
- How much does a solar permit cost in Williamson County?
- The structural mounting permit bills under the Section B101 valuation table starting at $15 for the first $1,000 plus $5 per additional thousand; the PV electrical connection is permitted separately through the state CORE system, per the county Schedule of Building Permit Fees. See the official fee schedule for current amounts.
- Where do you apply for a solar permit in Williamson County?
- You can apply through the Williamson County permit portal or contact the Williamson County Building Codes Department directly. The links are listed on this page.
- Can a homeowner pull a solar permit themselves in Williamson County?
- Under Tennessee law (T.C.A. 62-6-103; Tenn. Comp. R. & Regs. 0780-02-23-.01(1)(i), -.05(3), -.05(4)(b)2.; Tenn. Comp. R. & Regs. 0780-02-01-.05(2)(a)): Tennessee lets a homeowner act as their own builder. Under T.C.A. 62-6-103, as the State Fire Marshal's Office explains it, an owner may construct a single residence once every two years for personal use without a contractor's license, so long as the home is not for resale, lease, or rent, and anyone the homeowner hires whose portion of the work is $25,000 or more must be a licensed contractor. In state permit areas the owner pulls a property owner's permit, limited by rule to one per 24 month period, and the work is subject to the same inspections and fees as a contractor's job; proof of licensure is waived at permit purchase only when the owner personally performs the work. For electrical work, a homeowner may wire their own residence only after obtaining a residential property owner's electrical permit, which covers only the applicant and immediate family, does not authorize help from anyone unlicensed, and is limited to one per 12 month period unless the owner lost the home to fire or windstorm. Confirm how Williamson County applies this before you apply.
From the Library
What else needs a permit in Williamson County
Every other permit type we have verified for this jurisdiction, with the rule that applies here.
| Project | Permit needed? | Threshold | Typical fee |
|---|---|---|---|
| Deck Permit | Permit required | Not specified | Deck permits follow the county's general building permit valuation table: no fee for... |
| Electrical Permit | Permit required | Not specified | State-issued via the TN CORE system: a $5 issuing fee plus ampere-based inspection fees... |
| HVAC Permit | Permit required | Not specified | Mechanical Permit Fee Schedule: $10.00 permit fee plus $10.00 for the first $1,000 of... |
| Plumbing Permit | Permit required | Not specified | Plumbing Permit Fee Schedule: $10.00 for issuing each permit, plus $5.00 for water and... |
| Pool Permit | It depends | Swimming pools designed or able to hold water more than 30 inches deep in unincorporated Williamson County require a building permit; pools designed to hold 30 inches of water or less, temporary pools, above-ground pools with no permanent filter system or decking, and pools not left up year-round are exempt from the permit requirement. | No pool-specific line |
| Roof Replacement Permit | No permit needed | Not specified | No permit or fee |
Solar Permit in other Tennessee localities
Everything above, sourced
Code references
National and state model-code sections the general guidance on this page is drawn from. They are not Williamson County documents; the office above sets the local rules.
How this solar permit page for Williamson County was verified. 2 official sources: williamsoncounty-tn.gov, williamsoncounty-tn.gov; fee schedule: official document. Last checked by Mario Bailey, not confirmed with Williamson County Building Codes Department. Rules change; confirm before you build. How we verify.
Last checked: Report an error on this page
Compare Solar Permit requirements across Tennessee localities
Tennessee rule changes
- Metro Nashville posts a current codes fee schedule, replacing the 2010 sheet
BL2022-1215 (Metro Fee Schedule Legislation) ·