Solar Permit in King County, Washington
It depends
Sometimes, depending on the project
Before installing roof-mounted solar panels heavier than 4 lbs per sq ft in unincorporated King County
Issued byKing County Department of Local Services Permitting Division
By Mario Bailey, verified against official sources
Quick answer
In unincorporated King County roof-mounted solar photovoltaic panels that weigh less than 4 pounds per square foot on residences are exempt from a building permit. Installations exceeding that weight threshold require a building permit through MyBuildingPermit.com. The county provides a Solar PV Roof Mounted Residential Exemption checklist to confirm eligibility. These rules apply to unincorporated King County only.
Typical threshold: 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.
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
Before installing roof-mounted solar panels heavier than 4 lbs per sq ft in unincorporated King County
What a solar permit costs in King County
How King County compares in Washington
That is the most permissive solar permit threshold among the Washington jurisdictions we have verified: Bellevue and Snohomish County draw the line at 3.5.
| 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 Countythis page | 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 |
| Tacoma | Permit required | Not specified |
How to apply in King County
In King 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 King 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 King 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 King 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. King County Department of Local Services Permitting Division sets the exact checklist for King County.
Where to apply in King County:
King County Department of Local Services Permitting Division
- 919 SW Grady Way Suite 300, Renton, WA 98057
- Phone: (206) 296-6600
- Email: PermitQuestions@kingcounty.gov
Solar Permit in King County compared with nearby Washington localities
| Locality | Permit needed? | Threshold | What each Washington schedule says | Verified |
|---|---|---|---|---|
| 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... | |
| 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 | |
| Pierce County | Permit required | Not specified | Residential rooftop solar panel building permit base fee $173.00, plus $201.00 for... | |
| Seattle | Permit required | Not specified | Solar PV is permitted through the electrical permit: systems below 12kW are a flat $438... |
Inspections and closing out your permit
In King 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 King 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 King 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 King 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 King 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 King 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 King 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 King County permit portal or by phone at (206) 296-6600.
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 King County
- Confirm the requirement. Sometimes, depending on the project. Typical threshold: 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. Usually needed: Before installing roof-mounted solar panels heavier than 4 lbs per sq ft in unincorporated King County.
- Budget the fee. Most permit fees increased approximately 14% on January 1 2026 plus a $126 application screening fee. Official fee schedule.
- Apply. In King 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 King County permit portal.
- Keep the office details handy. King County Department of Local Services Permitting Division. Phone: (206) 296-6600. Address: 919 SW Grady Way Suite 300, Renton, WA 98057.
- Plan for inspections. In King 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 .
Permitting activity in King County
In 2024, King County authorized permits for 10,564 new residential housing units (2,352 single-family, 8,212 in multi-family buildings), valued at $2.7B, down from 10,601 the year before. That works out to about 4.5 permits per 1,000 residents.
Source: U.S. Census Bureau, Building Permits Survey, 2024 annual data · population 2,340,211.
About King County
King County has about 988,330 housing units. The median home is valued at $811,200, against a median household income of $122,148. About 56% of homes are owner-occupied, and the typical home was built around 1983.
Source: U.S. Census Bureau, American Community Survey 2023 5-year.
Frequently asked questions
- Do you need a solar permit in King County?
- In unincorporated King County roof-mounted solar photovoltaic panels that weigh less than 4 pounds per square foot on residences are exempt from a building permit. Installations exceeding that weight threshold require a building permit through MyBuildingPermit.com. The county provides a Solar PV Roof Mounted Residential Exemption checklist to confirm eligibility. These rules apply to unincorporated King County only. 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. Always confirm with the office before starting.
- How much does a solar permit cost in King County?
- Most permit fees increased approximately 14% on January 1 2026 plus a $126 application screening fee. See the official fee schedule for current amounts.
- Where do you apply for a solar permit in King County?
- You can apply through the King County permit portal or contact the King County Department of Local Services Permitting Division directly. The links are listed on this page.
- Can a homeowner pull a solar permit themselves in King 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 King County applies this before you apply.
From the Library
What else needs a permit in King 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 | uncovered decks 30 inches or less above ground do not require a building permit in unincorporated King County; decks over 30 inches above grade require a permit | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... |
| Electrical Permit | Permit required | Not specified | Set by state L&I, not King County, under WAC 296-46B-906 (effective 7/1/2026): new... |
| Fence Permit | It depends | fences 6 feet or less do not require a building permit in unincorporated King County; fences over 6 feet require a permit | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... |
| HVAC Permit | Permit required | Not specified | Mechanical installation-only permit is a flat $183 inspection fee covering up to six... |
| Patio Permit | It depends | at-grade patios and uncovered decks 30 inches or less above ground are exempt; covered patios and taller structures require a building permit | No separate patio line |
| Plumbing Permit | Permit required | Not specified | Issued by Public Health Seattle and King County rather than the county Permitting Division |
| Pool Permit | It depends | prefabricated above-ground pools less than 24 inches deep and not exceeding 5000 gallons are exempt; all other pools require a building permit in unincorporated King County | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... |
| Roof Replacement Permit | No permit needed | Not specified | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... |
| Shed Permit | It depends | storage sheds 200 sq ft or less as accessory to a residential house do not require a building permit in unincorporated King County; sheds over 200 sq ft require a permit | Most permit fees increased approximately 14% on January 1 2026 plus a $126 application... |
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 King County documents; the office above sets the local rules.
How this solar permit page for King County was verified. 2 official sources: kingcounty.gov, kingcounty.gov; fee schedule: official document. Last checked by Mario Bailey, not confirmed with King County Department of Local Services Permitting Division. 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
King County Department of Local Services Permitting Division
(206) 296-6600Permit portalWashington rule changes