Solar Permit in Thurston County, Washington
It depends
Sometimes, depending on the project
County permit for ground-mounted or commercial systems; state electrical permit for all systems
Issued byCommunity Planning and Economic Development - Building Development Center
By Mario Bailey, verified against official sources
Quick answer
Thurston County states there is no county permit required for residential rooftop solar PV systems. Ground-mounted and commercial solar systems do require county permits. Electrical permits from the Washington State Department of Labor and Industries are required for all solar projects.
Typical threshold: Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit.
Who is pulling this permit?
Apply yourself
Hire it out
Before you sign, ask the contractor:
- Who pulls the permit, you or me, and is the permit fee included in the bid?
- Which inspections will this job need, and who meets the inspector on site?
- Is your contractor license active in this locality, and under which business name?
When a permit is usually needed
County permit for ground-mounted or commercial systems; state electrical permit for all systems
What a solar permit costs in Thurston County
How Thurston County compares in Washington
| Jurisdiction | Permit needed? | Threshold |
|---|---|---|
| Bellevue | It depends | electrical permit required for all solar systems; building permit not required for rooftop single-family systems with dead load under 3.5 lbs per sq ft and panels no more than 18 inches above roof surface |
| Clark County | Permit required | Separate SOL permits are required for ground mounted units or panels mounted on existing buildings; in new construction the solar panels are included in the NHC or ADS permit. |
| King County | It depends | roof-mounted solar PV panels weighing less than 4 pounds per square foot on residences do not require a building permit; heavier installations require a permit |
| Pierce County | Permit required | Not specified |
| Seattle | Permit required | Not specified |
| Snohomish County | It depends | ground-mounted residential solar PV systems never need a building or mechanical permit; roof-mounted residential PV on a detached single-family house is exempt from a building/mechanical permit only if total dead load is 3.5 lbs per sq ft or less (up to 4.5 lbs per sq ft for frameless panels on a 3:12 or steeper slope, or 5 lbs per sq ft for frameless panels on a 5:12 or steeper slope), panels are mounted 18 inches or less above the roof surface, and an electrical permit has already been issued; a separate electrical permit through WA L&I is always required regardless |
| Thurston Countythis page | It depends | Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit. |
How to apply in Thurston County
In Thurston 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 Thurston 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 Thurston 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 Thurston 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. Community Planning and Economic Development - Building Development Center sets the exact checklist for Thurston County.
Where to apply in Thurston County:
Community Planning and Economic Development - Building Development Center
- 3000 Pacific Ave SE, Suite 100, Olympia, WA 98501
- Phone: 360-786-5490
- Email: permit@co.thurston.wa.us
Solar Permit in Thurston County compared with nearby Washington localities
| Locality | Permit needed? | Threshold | What each Washington schedule says | Verified |
|---|---|---|---|---|
| Thurston County | It depends | Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit. | Building permit and plan review fees are valuation based | |
| Bellevue | It depends | electrical permit required for all solar systems; building permit not required for rooftop single-family systems with dead load under 3.5 lbs per sq ft and panels no more than 18 inches above roof surface | Solar panel installations are electrical permits with fee by valuation per Table 6 of... | |
| Clark County | Permit required | Separate SOL permits are required for ground mounted units or panels mounted on existing buildings; in new construction the solar panels are included in the NHC or ADS permit. | Fees for separate SOL permits are based on construction value | |
| King County | It depends | roof-mounted solar PV panels weighing less than 4 pounds per square foot on residences do not require a building permit; heavier installations require a permit | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... | |
| Pierce County | Permit required | Not specified | Residential rooftop solar panel building permit base fee $173.00, plus $201.00 for... |
Inspections and closing out your permit
In Thurston 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 Thurston 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 Thurston 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 Thurston 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 Thurston 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 Thurston 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 Thurston 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 Thurston County permit portal or by phone at 360-786-5490.
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 Thurston County
- Confirm the requirement. Sometimes, depending on the project. Typical threshold: Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit. Usually needed: County permit for ground-mounted or commercial systems; state electrical permit for all systems.
- Budget the fee. Building permit and plan review fees are valuation based; L&I charges separate electrical permit fees. Official fee schedule.
- Apply. In Thurston 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 Thurston County permit portal.
- Keep the office details handy. Community Planning and Economic Development - Building Development Center. Phone: 360-786-5490. Address: 3000 Pacific Ave SE, Suite 100, Olympia, WA 98501.
- Plan for inspections. In Thurston 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 Thurston County?
- Thurston County states there is no county permit required for residential rooftop solar PV systems. Ground-mounted and commercial solar systems do require county permits. Electrical permits from the Washington State Department of Labor and Industries are required for all solar projects. Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit. Always confirm with the office before starting.
- How much does a solar permit cost in Thurston County?
- Building permit and plan review fees are valuation based; L&I charges separate electrical permit fees. See the official fee schedule for current amounts.
- Where do you apply for a solar permit in Thurston County?
- You can apply through the Thurston County permit portal or contact the Community Planning and Economic Development - Building Development Center directly. The links are listed on this page.
- Can a homeowner pull a solar permit themselves in Thurston County?
- Under Washington law (RCW 18.27.090(11), (12); RCW 19.28.261(1); RCW 18.106.150(1)): Washington lets homeowners do their own construction work, including the licensed trades, on property they own. RCW 18.27.090(12) exempts any person working on his or her own property from contractor registration, but the exemption does not apply if you do contractor type work for the purpose of selling, demolishing, or leasing the property, and the separate owner exemption in RCW 18.27.090(11) is lost if you sell or lease improved property owned less than 12 months. For electrical work, RCW 19.28.261 lets you wire your own residence, farm, or place of business without an electrician license, unless the work is on construction of a new building intended for rent, sale, or lease, or on property offered for sale within 12 months after you obtained it. RCW 18.106.150(1) gives the same kind of exemption for plumbing work at your own residence, farm, or place of business. These exemptions waive the license, not the permit: an owner doing electrical work still buys an L&I electrical work permit and passes inspection (WAC 296-46B-901), and building and plumbing permits still come from your local building department. Confirm how Thurston County applies this before you apply.
From the Library
What else needs a permit in Thurston 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 | It depends | Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck. | Building permit and plan review fees are valuation based |
| Electrical Permit | Permit required | Electrical work in unincorporated Thurston County requires a state electrical permit from L&I; the county itself does not issue electrical permits, with limited work exceptions under WAC 296-46B-901. | L&I sets electrical permit fees |
| Fence Permit | It depends | Fences 8 feet tall or shorter are exempt from a county building permit. | Building permit and plan review fees are valuation based |
| HVAC Permit | It depends | Heating and cooling equipment and gas piping require a Minor Permit, but replacement of electric forced-air heating units and water heaters is exempt. | Minor Permit fees apply |
| Patio Permit | It depends | Patios and porches are exempt if 30 inches or less from the ground to the top of the surface. | Building permit and plan review fees are valuation based |
| Plumbing Permit | Permit required | No permit is needed only to clear a blockage or to repair or stop a leak in a drain, water, soil, or vent pipe. | Minor Permit fees apply |
| Pool Permit | It depends | Pools are exempt only if prefabricated, entirely above ground, less than 24 inches deep, and under 5,000 gallons capacity. | Building permit and plan review fees are valuation based |
| Roof Replacement Permit | It depends | Roof repair and replacement is exempt unless the work adds skylights or changes, repairs, or replaces structural elements or the roof pitch or slope. | Building permit and plan review fees are valuation based |
| Shed Permit | It depends | One-story detached accessory buildings with no plumbing or electricity are exempt if under 200 square feet inside a county urban growth area or under 400 square feet outside a UGA. | Building permit and plan review fees are valuation based |
Solar Permit in other Washington localities
Everything above, sourced
Code references
National and state model-code sections the general guidance on this page is drawn from. They are not Thurston County documents; the office above sets the local rules.
How this solar permit page for Thurston County was verified. 3 official sources: thurstoncountywa.gov, thurstoncountywa.gov, lni.wa.gov; fee schedule: official document. Last checked by Mario Bailey, not confirmed with Community Planning and Economic Development - Building Development Center. Rules change; confirm before you build. How we verify.
Last checked: Report an error on this page
Compare Solar Permit requirements across Washington localities
Permit office
Community Planning and Economic Development - Building Development Center
360-786-5490Permit portalWashington rule changes