Solar Permit in King County, Washington

Permit required?

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.

When a permit is usually needed

Before installing roof-mounted solar panels heavier than 4 lbs per sq ft in unincorporated King County

Permit cost and what affects it

Most permit fees increased approximately 14% on January 1 2026 plus a $126 application screening fee

Permit costs generally depend on the project valuation, the scope of work, and the inspections required. Ask the office how the fee is calculated for your specific project.

Where to apply

• Official permit page
• Permit portal

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. The typical threshold is 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 Contact the office for current amounts.

How long does a solar permit take in King County?

Processing time for a solar permit in King County varies by workload and project scope. Contact the King County Department of Local Services Permitting Division for a current estimate.

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.

Official sources

• https://kingcounty.gov/en/dept/local-services/certificates-permits-licenses/permits/permits-inspections-codes-buildings-land-use/do-you-need-a-permit
• https://kingcounty.gov/en/dept/local-services/certificates-permits-licenses/permits/permits-inspections-codes-buildings-land-use/permit-forms-application-materials/single-family