King County, WA Solar Energy: Panel Permits (2026)
Key Facts
- Permit-free limit
- under 4 lbs/sq ft
- Height limit
- 18 inches above roof
- Who qualifies
- 1- and 2-family dwellings only
- Not exempt
- ground-mounted or oversized arrays
Summary
Unincorporated King County waives a building permit for roof-mounted home solar panels weighing under 4 pounds per square foot and rising no more than 18 inches above the roof; bigger or ground-mounted systems still need one.
Roof-mounted photovoltaic solar panels for one- and two-family dwellings that have a total dead load not exceeding four pounds per square foot and are no more than 18 inches (457 mm) above the roof or highest roof point on which they are mounted.
20. Ground-mounted wind turbines for one and two-family dwellings for which any portion of the unit does not exceed twelve feet (3.7 m) in height. Gas:
1. Portable heating or cooking appliances.
2. Replacement of any minor part that does not alter approval of equipment or make such equipment unsafe. Mechanical:
1. Portable heating or clothes drying appliances.
2. Portable ventilation appliances and equipment.
3. Portable cooling unit.
4. Steam, hot or chilled water piping within any heating or cooling equipment regulated by this code.
5. Replacement of any part that does not alter its approval or make it unsafe.
6. Portable evaporative cooler.
7. Self-contained refrigeration system containing 10 pounds (4.54 kg) or less of refrigerant and actuated by motors of one horsepower (746 W) or less.
8. Portable fuel cell appliances that are not connected to a fixed piping system and are not interconnected to a power grid. Exempted items shall still be subject to separate plumbing, electrical and mechanical permits.
Full Breakdown
Unincorporated King County exempts small rooftop solar from a building permit: King County Code 16.02.240 waives the permit for roof-mounted photovoltaic panels on one- and two-family dwellings when the array's dead load stays under 4 pounds per square foot and sits no more than 18 inches above the roof surface. Bigger arrays, ground-mounted systems, and installations on multifamily or commercial buildings still need a standard building permit from the Department of Local Services, Permitting Division, under the Title 27 fee schedule. Seattle, Bellevue, Kent, Renton and the county's other incorporated cities set their own separate solar permit rules.
Violations & Fines
Installing panels that exceed the weight or height exemption without pulling a permit can draw a stop-work order and Title 23 code-enforcement action from the Permitting Division.
Frequently Asked Questions
Do I need a building permit for rooftop solar in unincorporated King County?
What if my solar array is ground-mounted or larger than that?
Sources & Official References
Other rules in King County
Compare King County to another location·View the Washington solar energy overview
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